Commit graph

128 commits

Author SHA1 Message Date
Al Viro
121977187c Fix F_DUPFD_CLOEXEC breakage
Fix a braino in F_DUPFD_CLOEXEC; f_dupfd() expects flags for alloc_fd(),
get_unused_fd() etc and there clone-on-exec if O_CLOEXEC, not
FD_CLOEXEC.

Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 15:52:31 +09:00
Al Viro
63784dd02b fcntl: fix misannotations
__user * != * __user...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 22:20:20 -04:00
Al Viro
2903ff019b switch simple cases of fget_light to fdget
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 22:20:08 -04:00
Al Viro
fe17f22d7f take purely descriptor-related stuff from fcntl.c to file.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 21:09:57 -04:00
Al Viro
f33ff9927f take rlimit check to callers of expand_files()
... except for one in android, where the check is different
and already done in caller.  No need to recalculate rlimit
many times in alloc_fd() either.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 21:08:53 -04:00
Cyrill Gorcunov
1d151c337d c/r: fcntl: add F_GETOWNER_UIDS option
When we restore file descriptors we would like them to look exactly as
they were at dumping time.

With help of fcntl it's almost possible, the missing snippet is file
owners UIDs.

To be able to read their values the F_GETOWNER_UIDS is introduced.

This option is valid iif CONFIG_CHECKPOINT_RESTORE is turned on, otherwise
returning -EINVAL.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30 17:25:21 -07:00
Al Viro
545ec2c794 switch fcntl to fget_raw_light/fput_light
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-29 23:28:30 -04:00
Eric W. Biederman
8e96e3b7b8 userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-05-03 03:29:34 -07:00
David Howells
1dce27c5aa Wrap accesses to the fd_sets in struct fdtable
Wrap accesses to the fd_sets in struct fdtable (for recording open files and
close-on-exec flags) so that we can move away from using fd_sets since we
abuse the fd_set structs by not allocating the full-sized structure under
normal circumstances and by non-core code looking at the internals of the
fd_sets.

The first abuse means that use of FD_ZERO() on these fd_sets is not permitted,
since that cannot be told about their abnormal lengths.

This introduces six wrapper functions for setting, clearing and testing
close-on-exec flags and fd-is-open flags:

	void __set_close_on_exec(int fd, struct fdtable *fdt);
	void __clear_close_on_exec(int fd, struct fdtable *fdt);
	bool close_on_exec(int fd, const struct fdtable *fdt);
	void __set_open_fd(int fd, struct fdtable *fdt);
	void __clear_open_fd(int fd, struct fdtable *fdt);
	bool fd_is_open(int fd, const struct fdtable *fdt);

Note that I've prepended '__' to the names of the set/clear functions because
they require the caller to hold a lock to use them.

Note also that I haven't added wrappers for looking behind the scenes at the
the array.  Possibly that should exist too.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174942.23314.1364.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
2012-02-19 10:30:52 -08:00
Serge E. Hallyn
2e14967075 userns: rename is_owner_or_cap to inode_owner_or_capable
And give it a kernel-doc comment.

[akpm@linux-foundation.org: btrfs changed in linux-next]
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:47:13 -07:00
Al Viro
1abf0c718f New kind of open files - "location only".
New flag for open(2) - O_PATH.  Semantics:
	* pathname is resolved, but the file itself is _NOT_ opened
as far as filesystem is concerned.
	* almost all operations on the resulting descriptors shall
fail with -EBADF.  Exceptions are:
	1) operations on descriptors themselves (i.e.
		close(), dup(), dup2(), dup3(), fcntl(fd, F_DUPFD),
		fcntl(fd, F_DUPFD_CLOEXEC, ...), fcntl(fd, F_GETFD),
		fcntl(fd, F_SETFD, ...))
	2) fcntl(fd, F_GETFL), for a common non-destructive way to
		check if descriptor is open
	3) "dfd" arguments of ...at(2) syscalls, i.e. the starting
		points of pathname resolution
	* closing such descriptor does *NOT* affect dnotify or
posix locks.
	* permissions are checked as usual along the way to file;
no permission checks are applied to the file itself.  Of course,
giving such thing to syscall will result in permission checks (at
the moment it means checking that starting point of ....at() is
a directory and caller has exec permissions on it).

fget() and fget_light() return NULL on such descriptors; use of
fget_raw() and fget_raw_light() is needed to get them.  That protects
existing code from dealing with those things.

There are two things still missing (they come in the next commits):
one is handling of symlinks (right now we refuse to open them that
way; see the next commit for semantics related to those) and another
is descriptor passing via SCM_RIGHTS datagrams.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-15 02:21:45 -04:00
Namhyung Kim
3cd90ea42f vfs: sparse: add __FMODE_EXEC
FMODE_EXEC is a constant type of fmode_t but was used with normal integer
constants.  This results in following warnings from sparse.  Fix it using
new macro __FMODE_EXEC.

 fs/exec.c:116:58: warning: restricted fmode_t degrades to integer
 fs/exec.c:689:58: warning: restricted fmode_t degrades to integer
 fs/fcntl.c:777:9: warning: restricted fmode_t degrades to integer

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-02 16:03:19 -08:00
Linus Torvalds
55f335a885 fasync: Fix placement of FASYNC flag comment
In commit f7347ce4ee ("fasync: re-organize fasync entry insertion to
allow it under a spinlock") Arnd took an earlier patch of mine that had
the comment about the FASYNC flag above the wrong function.

When the fasync_add_entry() function was split to introduce the new
fasync_insert_entry() helper function, the code that actually cares
about the FASYNC bit moved to that new helper.

So just move the comment to the right point.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:17:02 -07:00
Linus Torvalds
f7347ce4ee fasync: re-organize fasync entry insertion to allow it under a spinlock
You currently cannot use "fasync_helper()" in an atomic environment to
insert a new fasync entry, because it will need to allocate the new
"struct fasync_struct".

Yet fcntl_setlease() wants to call this under lock_flocks(), which is in
the process of being converted from the BKL to a spinlock.

In order to fix this, this abstracts out the actual fasync list
insertion and the fasync allocations into functions of their own, and
teaches fs/locks.c to pre-allocate the fasync_struct entry.  That way
the actual list insertion can happen while holding the required
spinlock.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bfields@redhat.com: rebase on top of my changes to Arnd's patch]
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2010-10-27 22:06:17 +02:00
James Bottomley
3ab04d5cf9 vfs: take O_NONBLOCK out of the O_* uniqueness test
O_NONBLOCK on parisc has a dual value:

#define O_NONBLOCK	000200004 /* HPUX has separate NDELAY & NONBLOCK */

It is caught by the O_* bits uniqueness check and leads to a parisc
compile error.  The fix would be to take O_NONBLOCK out.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Cc: Jamie Lokier <jamie@shareable.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-09 18:57:25 -07:00
Wu Fengguang
454eedb890 vfs: O_* bit numbers uniqueness check
The O_* bit numbers are defined in 20+ arch/*, and can silently overlap.
Add a compile time check to ensure the uniqueness as suggested by David
Miller.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: David Miller <davem@davemloft.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Jamie Lokier <jamie@shareable.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11 08:59:02 -07:00
Andrew Morton
f4985dc714 fs/fcntl.c:kill_fasync_rcu() fa_lock must be IRQ-safe
Fix a lockdep-splat-causing regression introduced by commit 989a297920
("fasync: RCU and fine grained locking").

kill_fasync() can be called from both process and hard-irq context, so
fa_lock must be taken with IRQs disabled.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16230

Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Dominik Brodowski <linux@dominikbrodowski.net>
Tested-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Maciej Rutecki <maciej.rutecki@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-06-29 15:29:32 -07:00
Dan Carpenter
5b54470dad fcntl: return -EFAULT if copy_to_user fails
copy_to_user() returns the number of bytes remaining, but we want to
return -EFAULT.
	ret = fcntl(fd, F_SETOWN_EX, NULL);
With the original code ret would be 8 here.

V2: Takuya Yoshikawa pointed out a similar issue in f_getown_ex()

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-06-04 17:16:28 -04:00
Jens Axboe
ee9a3607fb Merge branch 'master' into for-2.6.35
Conflicts:
	fs/ext3/fsync.c

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-05-21 21:27:26 +02:00
Jens Axboe
35f3d14dbb pipe: add support for shrinking and growing pipes
This patch adds F_GETPIPE_SZ and F_SETPIPE_SZ fcntl() actions for
growing and shrinking the size of a pipe and adjusts pipe.c and splice.c
(and relay and network splice) usage to work with these larger (or smaller)
pipes.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-05-21 21:12:40 +02:00
Eric Dumazet
989a297920 fasync: RCU and fine grained locking
kill_fasync() uses a central rwlock, candidate for RCU conversion, to
avoid cache line ping pongs on SMP.

fasync_remove_entry() and fasync_add_entry() can disable IRQS on a short
section instead during whole list scan.

Use a spinlock per fasync_struct to synchronize kill_fasync_rcu() and
fasync_{remove|add}_entry(). This spinlock is IRQ safe, so sock_fasync()
doesnt need its own implementation and can use fasync_helper(), to
reduce code size and complexity.

We can remove __kill_fasync() direct use in net/socket.c, and rename it
to kill_fasync_rcu().

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-21 16:19:29 -07:00
Jiri Slaby
d554ed895d fs: use rlimit helpers
Make sure compiler won't do weird things with limits.  E.g.  fetching them
twice may return 2 different values after writable limits are implemented.

I.e.  either use rlimit helpers added in commit 3e10e716ab ("resource:
add helpers for fetching rlimits") or ACCESS_ONCE if not applicable.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 11:26:29 -08:00
Linus Torvalds
80e1e82398 Fix race in tty_fasync() properly
This reverts commit 7036251180 ("tty: fix race in tty_fasync") and
commit b04da8bfdf ("fnctl: f_modown should call write_lock_irqsave/
restore") that tried to fix up some of the fallout but was incomplete.

It turns out that we really cannot hold 'tty->ctrl_lock' over calling
__f_setown, because not only did that cause problems with interrupt
disables (which the second commit fixed), it also causes a potential
ABBA deadlock due to lock ordering.

Thanks to Tetsuo Handa for following up on the issue, and running
lockdep to show the problem.  It goes roughly like this:

 - f_getown gets filp->f_owner.lock for reading without interrupts
   disabled, so an interrupt that happens while that lock is held can
   cause a lockdep chain from f_owner.lock -> sighand->siglock.

 - at the same time, the tty->ctrl_lock -> f_owner.lock chain that
   commit 7036251180 introduced, together with the pre-existing
   sighand->siglock -> tty->ctrl_lock chain means that we have a lock
   dependency the other way too.

So instead of extending tty->ctrl_lock over the whole __f_setown() call,
we now just take a reference to the 'pid' structure while holding the
lock, and then release it after having done the __f_setown.  That still
guarantees that 'struct pid' won't go away from under us, which is all
we really ever needed.

Reported-and-tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Américo Wang <xiyou.wangcong@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-07 10:26:01 -08:00
Greg Kroah-Hartman
b04da8bfdf fnctl: f_modown should call write_lock_irqsave/restore
Commit 7036251180 exposed that f_modown()
should call write_lock_irqsave instead of just write_lock_irq so that
because a caller could have a spinlock held and it would not be good to
renable interrupts.

Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Tavis Ormandy <taviso@google.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-26 17:25:38 -08:00
Linus Torvalds
53281b6d34 fasync: split 'fasync_helper()' into separate add/remove functions
Yes, the add and remove cases do share the same basic loop and the
locking, but the compiler can inline and then CSE some of the end result
anyway.  And splitting it up makes the code way easier to follow,
and makes it clearer exactly what the semantics are.

In particular, we must make sure that the FASYNC flag in file->f_flags
exactly matches the state of "is this file on any fasync list", since
not only is that flag visible to user space (F_GETFL), but we also use
that flag to check whether we need to remove any fasync entries on file
close.

We got that wrong for the case of a mixed use of file locking (which
tries to remove any fasync entries for file leases) and fasync.

Splitting the function up also makes it possible to do some future
optimizations without making the function even messier.  In particular,
since the FASYNC flag has to match the state of "is this on a list", we
can do the following future optimizations:

 - on remove, we don't even need to get the locks and traverse the list
   if FASYNC isn't set, since we can know a priori that there is no
   point (this is effectively the same optimization that we already do
   in __fput() wrt removing fasync on file close)

 - on add, we can use the FASYNC flag to decide whether we are changing
   an existing entry or need to allocate a new one.

but this is just the cleanup + fix for the FASYNC flag.

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Tested-by: Tavis Ormandy <taviso@google.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 10:05:29 -08:00
Peter Zijlstra
978b4053ae fcntl: rename F_OWNER_GID to F_OWNER_PGRP
This is for consistency with various ioctl() operations that include the
suffix "PGRP" in their names, and also for consistency with PRIO_PGRP,
used with setpriority() and getpriority().  Also, using PGRP instead of
GID avoids confusion with the common abbreviation of "group ID".

I'm fine with anything that makes it more consistent, and if PGRP is what
is the predominant abbreviation then I see no need to further confuse
matters by adding a third one.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-17 17:40:33 -08:00
Peter Zijlstra
ba0a6c9f6f fcntl: add F_[SG]ETOWN_EX
In order to direct the SIGIO signal to a particular thread of a
multi-threaded application we cannot, like suggested by the manpage, put a
TID into the regular fcntl(F_SETOWN) call.  It will still be send to the
whole process of which that thread is part.

Since people do want to properly direct SIGIO we introduce F_SETOWN_EX.

The need to direct SIGIO comes from self-monitoring profiling such as with
perf-counters.  Perf-counters uses SIGIO to notify that new sample data is
available.  If the signal is delivered to the same task that generated the
new sample it can augment that data by inspecting the task's user-space
state right after it returns from the kernel.  This is esp.  convenient
for interpreted or virtual machine driven environments.

Both F_SETOWN_EX and F_GETOWN_EX take a pointer to a struct f_owner_ex
as argument:

struct f_owner_ex {
	int   type;
	pid_t pid;
};

Where type is one of F_OWNER_TID, F_OWNER_PID or F_OWNER_GID.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: stephane eranian <eranian@googlemail.com>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:21:01 -07:00
Oleg Nesterov
06f1631a16 signals: send_sigio: use do_send_sig_info() to avoid check_kill_permission()
group_send_sig_info()->check_kill_permission() assumes that current is the
sender and uses current_cred().

This is not true in send_sigio_to_task() case.  From the security pov the
sender is not current, but the task which did fcntl(F_SETOWN), that is why
we have sigio_perm() which uses the right creds to check.

Fortunately, send_sigio() always sends either SEND_SIG_PRIV or
SI_FROMKERNEL() signal, so check_kill_permission() does nothing.  But
still it would be tidier to avoid this bogus security check and save a
couple of cycles.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stephane eranian <eranian@googlemail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:21:01 -07:00
Alexey Dobriyan
405f55712d headers: smp_lock.h redux
* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
  It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

  This will make hardirq.h inclusion cheaper for every PREEMPT=n config
  (which includes allmodconfig/allyesconfig, BTW)

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-12 12:22:34 -07:00
Oleg Nesterov
8eeee4e2f0 send_sigio_to_task: sanitize the usage of fown->signum
send_sigio_to_task() reads fown->signum several times, we can race with
F_SETSIG which changes ->signum lockless.  In theory, this can fool
security checks or we can call group_send_sig_info() with the wrong
->si_signo which does not match "int sig".

Change the code to cache ->signum.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 15:36:17 -07:00
Oleg Nesterov
2f38d70fb4 shift current_cred() from __f_setown() to f_modown()
Shift current_cred() from __f_setown() to f_modown(). This reduces
the number of arguments and saves 48 bytes from fs/fcntl.o.

[ Note: this doesn't clear euid/uid when pid is set to NULL.  But if
  f_owner.pid == NULL we never use f_owner.uid/euid.  Otherwise we'd
  have a bug anyway: we must not send signals if pid was reset to NULL.  ]

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 14:19:00 -07:00
Jeff Mahoney
2b79bc4f7e dup2: Fix return value with oldfd == newfd and invalid fd
The return value of dup2 when oldfd == newfd and the fd isn't valid is
not getting properly sign extended.  We end up with 4294967287 instead
of -EBADF.

I've reproduced this on SLE11 (2.6.27.21), openSUSE Factory
(2.6.29-rc5), and Ubuntu 9.04 (2.6.28).

This patch uses a signed int for the error value so it is properly
extended.

Commit 6c5d0512a0 introduced this
regression.

Reported-by: Jiri Dluhos <jdluhos@novell.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-11 12:18:06 -07:00
Jonathan Corbet
4a6a449969 Fix a lockdep warning in fasync_helper()
Lockdep gripes if file->f_lock is taken in a no-IRQ situation, since that
is not always the case.  We don't really want to disable IRQs for every
acquisition of f_lock; instead, just move it outside of fasync_lock.

Reported-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2009-03-30 08:00:24 -06:00
Jonathan Corbet
60aa49243d Rationalize fasync return values
Most fasync implementations do something like:

     return fasync_helper(...);

But fasync_helper() will return a positive value at times - a feature used
in at least one place.  Thus, a number of other drivers do:

     err = fasync_helper(...);
     if (err < 0)
             return err;
     return 0;

In the interests of consistency and more concise code, it makes sense to
map positive return values onto zero where ->fasync() is called.

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2009-03-16 08:34:35 -06:00
Jonathan Corbet
76398425bb Move FASYNC bit handling to f_op->fasync()
Removing the BKL from FASYNC handling ran into the challenge of keeping the
setting of the FASYNC bit in filp->f_flags atomic with regard to calls to
the underlying fasync() function.  Andi Kleen suggested moving the handling
of that bit into fasync(); this patch does exactly that.  As a result, we
have a couple of internal API changes: fasync() must now manage the FASYNC
bit, and it will be called without the BKL held.

As it happens, every fasync() implementation in the kernel with one
exception calls fasync_helper().  So, if we make fasync_helper() set the
FASYNC bit, we can avoid making any changes to the other fasync()
functions - as long as those functions, themselves, have proper locking.
Most fasync() implementations do nothing but call fasync_helper() - which
has its own lock - so they are easily verified as correct.  The BKL had
already been pushed down into the rest.

The networking code has its own version of fasync_helper(), so that code
has been augmented with explicit FASYNC bit handling.

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: David Miller <davem@davemloft.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2009-03-16 08:32:27 -06:00
Jonathan Corbet
db1dd4d376 Use f_lock to protect f_flags
Traditionally, changes to struct file->f_flags have been done under BKL
protection, or with no protection at all.  This patch causes all f_flags
changes after file open/creation time to be done under protection of
f_lock.  This allows the removal of some BKL usage and fixes a number of
longstanding (if microscopic) races.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2009-03-16 08:32:27 -06:00
Heiko Carstens
a26eab2400 [CVE-2009-0029] System call wrappers part 15
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:24 +01:00
James Morris
cbacc2c7f0 Merge branch 'next' into for-linus 2008-12-25 11:40:09 +11:00
Jonathan Corbet
218d11a8b0 Fix a race condition in FASYNC handling
Changeset a238b790d5 (Call fasync()
functions without the BKL) introduced a race which could leave
file->f_flags in a state inconsistent with what the underlying
driver/filesystem believes.  Revert that change, and also fix the same
races in ioctl_fioasync() and ioctl_fionbio().

This is a minimal, short-term fix; the real fix will not involve the
BKL.

Reported-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-05 15:35:10 -08:00
David Howells
c69e8d9c01 CRED: Use RCU to access another task's creds and to release a task's own creds
Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:19 +11:00
David Howells
86a264abe5 CRED: Wrap current->cred and a few other accessors
Wrap current->cred and a few other accessors to hide their actual
implementation.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:18 +11:00
David Howells
b6dff3ec5e CRED: Separate task security context from task_struct
Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:16 +11:00
David Howells
da9592edeb CRED: Wrap task credential accesses in the filesystem subsystem
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:05 +11:00
Al Viro
1b7e190b47 [PATCH] clean dup2() up a bit
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-08-01 11:25:24 -04:00
Al Viro
1027abe882 [PATCH] merge locate_fd() and get_unused_fd()
New primitive: alloc_fd(start, flags).  get_unused_fd() and
get_unused_fd_flags() become wrappers on top of it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-08-01 11:25:23 -04:00
Al Viro
4e1e018ecc [PATCH] fix RLIM_NOFILE handling
* dup2() should return -EBADF on exceeded sysctl_nr_open
* dup() should *not* return -EINVAL even if you have rlimit set to 0;
  it should get -EMFILE instead.

Check for orig_start exceeding rlimit taken to sys_fcntl().
Failing expand_files() in dup{2,3}() now gets -EMFILE remapped to -EBADF.
Consequently, remaining checks for rlimit are taken to expand_files().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26 20:53:45 -04:00
Al Viro
6c5d0512a0 [PATCH] get rid of corner case in dup3() entirely
Since Ulrich is OK with getting rid of dup3(fd, fd, flags) completely,
to hell the damn thing goes.  Corner case for dup2() is handled in
sys_dup2() (complete with -EBADF if dup2(fd, fd) is called with fd
that is not open), the rest is done in dup3().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26 20:53:44 -04:00
Ulrich Drepper
3c333937ee [PATCH] dup3 fix
Al Viro notice one cornercase that the new dup3() code.  The dup2()
function, as a special case, handles dup-ing to the same file
descriptor.  In this case the current dup3() code does nothing at
all.  I.e., it ingnores the flags parameter.  This shouldn't happen,
the close-on-exec flag should be set if requested.

In case the O_CLOEXEC bit in the flags parameter is not set the
dup3() function should behave in this respect identical to dup2().
This means dup3(fd, fd, 0) should not actively reset the c-o-e
flag.

The patch below implements this minor change.

[AV: credits to Artur Grabowski for bringing that up as potential subtle point
in dup2() behaviour]

Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26 20:53:39 -04:00
Ulrich Drepper
336dd1f70f flag parameters: dup2
This patch adds the new dup3 syscall.  It extends the old dup2 syscall by one
parameter which is meant to hold a flag value.  Support for the O_CLOEXEC flag
is added in this patch.

The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <sys/syscall.h>

#ifndef __NR_dup3
# ifdef __x86_64__
#  define __NR_dup3 292
# elif defined __i386__
#  define __NR_dup3 330
# else
#  error "need __NR_dup3"
# endif
#endif

int
main (void)
{
  int fd = syscall (__NR_dup3, 1, 4, 0);
  if (fd == -1)
    {
      puts ("dup3(0) failed");
      return 1;
    }
  int coe = fcntl (fd, F_GETFD);
  if (coe == -1)
    {
      puts ("fcntl failed");
      return 1;
    }
  if (coe & FD_CLOEXEC)
    {
      puts ("dup3(0) set close-on-exec flag");
      return 1;
    }
  close (fd);

  fd = syscall (__NR_dup3, 1, 4, O_CLOEXEC);
  if (fd == -1)
    {
      puts ("dup3(O_CLOEXEC) failed");
      return 1;
    }
  coe = fcntl (fd, F_GETFD);
  if (coe == -1)
    {
      puts ("fcntl failed");
      return 1;
    }
  if ((coe & FD_CLOEXEC) == 0)
    {
      puts ("dup3(O_CLOEXEC) set close-on-exec flag");
      return 1;
    }
  close (fd);

  puts ("OK");

  return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 10:47:28 -07:00
Jonathan Corbet
a238b790d5 Call fasync() functions without the BKL
lock_kernel() calls have been pushed down into code which needs it, so
there is no need to take the BKL at this level anymore.

This work inspired and aided by Andi Kleen's unlocked_fasync() patches.

Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2008-07-02 15:06:28 -06:00
Al Viro
9f3acc3140 [PATCH] split linux/file.h
Initial splitoff of the low-level stuff; taken to fdtable.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-01 13:08:16 -04:00
Al Viro
f8f95702f0 [PATCH] sanitize locate_fd()
* 'file' argument is unused; lose it.
* move setting flags from the caller (dupfd()) to locate_fd();
  pass cloexec flag as new argument.  Note that files_fdtable()
  that used to be in dupfd() isn't needed in the place in
  locate_fd() where the moved code ends up - we know that ->file_lock
  hadn't been dropped since the last time we calculated fdt because
  we can get there only if expand_files() returns 0 and it doesn't
  drop/reacquire in that case.
* move getting/dropping ->file_lock into locate_fd().  Now the caller
  doesn't need to do anything with files_struct *files anymore and
  we can move that inside locate_fd() as well, killing the
  struct files_struct * argument.

At that point locate_fd() is extremely similar to get_unused_fd_flags()
and the next patches will merge those two.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-25 09:24:05 -04:00
Harvey Harrison
fc9b52cd8f fs: remove fastcall, it is always empty
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:31 -08:00
Pavel Emelyanov
6c5f3e7b43 Pidns: make full use of xxx_vnr() calls
Some time ago the xxx_vnr() calls (e.g.  pid_vnr or find_task_by_vpid) were
_all_ converted to operate on the current pid namespace.  After this each call
like xxx_nr_ns(foo, current->nsproxy->pid_ns) is nothing but a xxx_vnr(foo)
one.

Switch all the xxx_nr_ns() callers to use the xxx_vnr() calls where
appropriate.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Reviewed-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:29 -08:00
Pavel Emelyanov
b488893a39 pid namespaces: changes to show virtual ids to user
This is the largest patch in the set. Make all (I hope) the places where
the pid is shown to or get from user operate on the virtual pids.

The idea is:
 - all in-kernel data structures must store either struct pid itself
   or the pid's global nr, obtained with pid_nr() call;
 - when seeking the task from kernel code with the stored id one
   should use find_task_by_pid() call that works with global pids;
 - when showing pid's numerical value to the user the virtual one
   should be used, but however when one shows task's pid outside this
   task's namespace the global one is to be used;
 - when getting the pid from userspace one need to consider this as
   the virtual one and use appropriate task/pid-searching functions.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: yet nuther build fix]
[akpm@linux-foundation.org: remove unneeded casts]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:40 -07:00
Ulrich Drepper
22d2b35b20 F_DUPFD_CLOEXEC implementation
One more small change to extend the availability of creation of file
descriptors with FD_CLOEXEC set.  Adding a new command to fcntl() requires
no new system call and the overall impact on code size if minimal.

If this patch gets accepted we will also add this change to the next
revision of the POSIX spec.

To test the patch, use the following little program.  Adjust the value of
F_DUPFD_CLOEXEC appropriately.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#ifndef F_DUPFD_CLOEXEC
# define F_DUPFD_CLOEXEC 12
#endif

int
main (int argc, char *argv[])
{
  if  (argc > 1)
    {
      if (fcntl (3, F_GETFD) == 0)
	{
	  puts ("descriptor not closed");
	  exit (1);
	}
      if (errno != EBADF)
	{
	  puts ("error not EBADF");
	  exit (1);
	}

      exit (0);
    }
  int fd = fcntl (STDOUT_FILENO, F_DUPFD_CLOEXEC, 0);
  if (fd == -1 && errno == EINVAL)
    {
      puts ("F_DUPFD_CLOEXEC not supported");
      return 0;
    }
  if (fd != 3)
    {
      puts ("program called with descriptors other than 0,1,2");
      return 1;
    }

  execl ("/proc/self/exe", "/proc/self/exe", "1", NULL);
  puts ("execl failed");
  return 1;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <linux-arch@vger.kernel.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:43:01 -07:00
Paul Mundt
20c2df83d2 mm: Remove slab destructors from kmem_cache_create().
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-07-20 10:11:58 +09:00
Satyam Sharma
3bd858ab1c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check
Introduce is_owner_or_cap() macro in fs.h, and convert over relevant
users to it. This is done because we want to avoid bugs in the future
where we check for only effective fsuid of the current task against a
file's owning uid, without simultaneously checking for CAP_FOWNER as
well, thus violating its semantics.
[ XFS uses special macros and structures, and in general looked ...
untouchable, so we leave it alone -- but it has been looked over. ]

The (current->fsuid != inode->i_uid) check in generic_permission() and
exec_permission_lite() is left alone, because those operations are
covered by CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH. Similarly operations
falling under the purview of CAP_CHOWN and CAP_LEASE are also left alone.

Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Cc: Al Viro <viro@ftp.linux.org.uk>
Acked-by: Serge E. Hallyn <serge@hallyn.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 12:00:03 -07:00
Vadim Lobanov
bbea9f6966 [PATCH] fdtable: Make fdarray and fdsets equal in size
Currently, each fdtable supports three dynamically-sized arrays of data: the
fdarray and two fdsets.  The code allows the number of fds supported by the
fdarray (fdtable->max_fds) to differ from the number of fds supported by each
of the fdsets (fdtable->max_fdset).

In practice, it is wasteful for these two sizes to differ: whenever we hit a
limit on the smaller-capacity structure, we will reallocate the entire fdtable
and all the dynamic arrays within it, so any delta in the memory used by the
larger-capacity structure will never be touched at all.

Rather than hogging this excess, we shouldn't even allocate it in the first
place, and keep the capacities of the fdarray and the fdsets equal.  This
patch removes fdtable->max_fdset.  As an added bonus, most of the supporting
code becomes simpler.

Signed-off-by: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-10 09:57:22 -08:00
Josef "Jeff" Sipek
0f7fc9e4d0 [PATCH] VFS: change struct file to use struct path
This patch changes struct file to use struct path instead of having
independent pointers to struct dentry and struct vfsmount, and converts all
users of f_{dentry,vfsmnt} in fs/ to use f_path.{dentry,mnt}.

Additionally, it adds two #define's to make the transition easier for users of
the f_dentry and f_vfsmnt.

Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:41 -08:00
Christoph Lameter
e18b890bb0 [PATCH] slab: remove kmem_cache_t
Replace all uses of kmem_cache_t with struct kmem_cache.

The patch was generated using the following script:

	#!/bin/sh
	#
	# Replace one string by another in all the kernel sources.
	#

	set -e

	for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
		quilt add $file
		sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
		mv /tmp/$$ $file
		quilt refresh
	done

The script was run like this

	sh replace kmem_cache_t "struct kmem_cache"

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:25 -08:00
Christoph Lameter
e94b176609 [PATCH] slab: remove SLAB_KERNEL
SLAB_KERNEL is an alias of GFP_KERNEL.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:24 -08:00
Eric W. Biederman
43fa1adb93 [PATCH] file: Add locking to f_getown
This has been needed for a long time, but now with the advent of a
reference counted struct pid there are real consequences for getting this
wrong.

Someone I think it was Oleg Nesterov pointed out that this construct was
missing locking, when I introduced struct pid.  After taking time to review
the locking construct already present I figured out which lock needs to be
taken.  The other paths that access f_owner.pid take either the f_owner
read or the write lock.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02 07:57:15 -07:00
Eric W. Biederman
609d7fa956 [PATCH] file: modify struct fown_struct to use a struct pid
File handles can be requested to send sigio and sigurg to processes.  By
tracking the destination processes using struct pid instead of pid_t we make
the interface safe from all potential pid wrap around problems.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02 07:57:14 -07:00
Eric Sesterhenn
f6298aab2e BUG_ON() Conversion in fs/fcntl.c
this changes if() BUG(); constructs to BUG_ON() which is
cleaner and can better optimized away

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-04-02 13:37:19 +02:00
Eric Dumazet
fa3536cc14 [PATCH] Use __read_mostly on some hot fs variables
I discovered on oprofile hunting on a SMP platform that dentry lookups were
slowed down because d_hash_mask, d_hash_shift and dentry_hashtable were in
a cache line that contained inodes_stat.  So each time inodes_stats is
changed by a cpu, other cpus have to refill their cache line.

This patch moves some variables to the __read_mostly section, in order to
avoid false sharing.  RCU dentry lookups can go full speed.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26 08:56:56 -08:00
Eric Dumazet
0c9e63fd38 [PATCH] Shrinks sizeof(files_struct) and better layout
1) Reduce the size of (struct fdtable) to exactly 64 bytes on 32bits
   platforms, lowering kmalloc() allocated space by 50%.

2) Reduce the size of (files_struct), using a special 32 bits (or
   64bits) embedded_fd_set, instead of a 1024 bits fd_set for the
   close_on_exec_init and open_fds_init fields.  This save some ram (248
   bytes per task) as most tasks dont open more than 32 files.  D-Cache
   footprint for such tasks is also reduced to the minimum.

3) Reduce size of allocated fdset.  Currently two full pages are
   allocated, that is 32768 bits on x86 for example, and way too much.  The
   minimum is now L1_CACHE_BYTES.

UP and SMP should benefit from this patch, because most tasks will touch
only one cache line when open()/close() stdin/stdout/stderr (0/1/2),
(next_fd, close_on_exec_init, open_fds_init, fd_array[0 ..  2] being in the
same cache line)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23 07:38:09 -08:00
dean gaudet
7d95c8f27d [PATCH] fcntl F_SETFL and read-only IS_APPEND files
There is code in setfl() which attempts to preserve the O_APPEND flag on
IS_APPEND files...  however IS_APPEND files could also be opened O_RDONLY
and in that case setfl() should not require O_APPEND...

coreutils 5.93 tail -f attempts to set O_NONBLOCK even on regular files...
unfortunately if you try this on an append-only log file the result is
this:

fcntl64(3, F_GETFL)                     = 0x8000 (flags O_RDONLY|O_LARGEFILE)
fcntl64(3, F_SETFL, O_RDONLY|O_NONBLOCK|O_LARGEFILE) = -1 EPERM (Operation not permitted)

I offer up the patch below as one way of fixing the problem...  i've tested
it fixes the problem with tail -f but haven't really tested beyond that.

(I also reported the coreutils bug upstream... it shouldn't fail imho...
<https://savannah.gnu.org/bugs/index.php?func=detailitem&item_id=15473>)

Signed-off-by: dean gaudet <dean@arctic.org>
Cc: Al Viro <viro@ftp.linux.org.uk>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-03 08:32:07 -08:00
Arjan van de Ven
858119e159 [PATCH] Unlinline a bunch of other functions
Remove the "inline" keyword from a bunch of big functions in the kernel with
the goal of shrinking it by 30kb to 40kb

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-14 18:27:06 -08:00
Randy Dunlap
16f7e0fe2e [PATCH] capable/capability.h (fs/)
fs: Use <linux/capability.h> where capable() is used.

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11 18:42:13 -08:00
Oleg Nesterov
850d6fbe70 [PATCH] sigio: cleanup, don't take tasklist twice
The only user of send_sigio_to_task() already holds tasklist_lock, so it is
better not to send the signal via send_group_sig_info() (which takes
tasklist recursively) but use group_send_sig_info().

The same change in send_sigurg()->send_sigurg_to_task().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:57 -08:00
Dipankar Sarma
b835996f62 [PATCH] files: lock-free fd look-up
With the use of RCU in files structure, the look-up of files using fds can now
be lock-free.  The lookup is protected by rcu_read_lock()/rcu_read_unlock().
This patch changes the readers to use lock-free lookup.

Signed-off-by: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Ravikiran Thirumalai <kiran_th@gmail.com>
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 13:57:55 -07:00
Dipankar Sarma
ab2af1f500 [PATCH] files: files struct with RCU
Patch to eliminate struct files_struct.file_lock spinlock on the reader side
and use rcu refcounting rcuref_xxx api for the f_count refcounter.  The
updates to the fdtable are done by allocating a new fdtable structure and
setting files->fdt to point to the new structure.  The fdtable structure is
protected by RCU thereby allowing lock-free lookup.  For fd arrays/sets that
are vmalloced, we use keventd to free them since RCU callbacks can't sleep.  A
global list of fdtable to be freed is not scalable, so we use a per-cpu list.
If keventd is already handling the current cpu's work, we use a timer to defer
queueing of that work.

Since the last publication, this patch has been re-written to avoid using
explicit memory barriers and use rcu_assign_pointer(), rcu_dereference()
premitives instead.  This required that the fd information is kept in a
separate structure (fdtable) and updated atomically.

Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 13:57:55 -07:00
Dipankar Sarma
badf16621c [PATCH] files: break up files struct
In order for the RCU to work, the file table array, sets and their sizes must
be updated atomically.  Instead of ensuring this through too many memory
barriers, we put the arrays and their sizes in a separate structure.  This
patch takes the first step of putting the file table elements in a separate
structure fdtable that is embedded withing files_struct.  It also changes all
the users to refer to the file table using files_fdtable() macro.  Subsequent
applciation of RCU becomes easier after this.

Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 13:57:55 -07:00
Peter Staubach
c293621bbf [PATCH] stale POSIX lock handling
I believe that there is a problem with the handling of POSIX locks, which
the attached patch should address.

The problem appears to be a race between fcntl(2) and close(2).  A
multithreaded application could close a file descriptor at the same time as
it is trying to acquire a lock using the same file descriptor.  I would
suggest that that multithreaded application is not providing the proper
synchronization for itself, but the OS should still behave correctly.

SUS3 (Single UNIX Specification Version 3, read: POSIX) indicates that when
a file descriptor is closed, that all POSIX locks on the file, owned by the
process which closed the file descriptor, should be released.

The trick here is when those locks are released.  The current code releases
all locks which exist when close is processing, but any locks in progress
are handled when the last reference to the open file is released.

There are three cases to consider.

One is the simple case, a multithreaded (mt) process has a file open and
races to close it and acquire a lock on it.  In this case, the close will
release one reference to the open file and when the fcntl is done, it will
release the other reference.  For this situation, no locks should exist on
the file when both the close and fcntl operations are done.  The current
system will handle this case because the last reference to the open file is
being released.

The second case is when the mt process has dup(2)'d the file descriptor.
The close will release one reference to the file and the fcntl, when done,
will release another, but there will still be at least one more reference
to the open file.  One could argue that the existence of a lock on the file
after the close has completed is okay, because it was acquired after the
close operation and there is still a way for the application to release the
lock on the file, using an existing file descriptor.

The third case is when the mt process has forked, after opening the file
and either before or after becoming an mt process.  In this case, each
process would hold a reference to the open file.  For each process, this
degenerates to first case above.  However, the lock continues to exist
until both processes have released their references to the open file.  This
lock could block other lock requests.

The changes to release the lock when the last reference to the open file
aren't quite right because they would allow the lock to exist as long as
there was a reference to the open file.  This is too long.

The new proposed solution is to add support in the fcntl code path to
detect a race with close and then to release the lock which was just
acquired when such as race is detected.  This causes locks to be released
in a timely fashion and for the system to conform to the POSIX semantic
specification.

This was tested by instrumenting a kernel to detect the handling locks and
then running a program which generates case #3 above.  A dangling lock
could be reliably generated.  When the changes to detect the close/fcntl
race were added, a dangling lock could no longer be generated.

Cc: Matthew Wilcox <willy@debian.org>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-27 16:26:06 -07:00
Jesper Juhl
7ed20e1ad5 [PATCH] convert that currently tests _NSIG directly to use valid_signal()
Convert most of the current code that uses _NSIG directly to instead use
valid_signal().  This avoids gcc -W warnings and off-by-one errors.

Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 08:59:14 -07:00
Bharath Ramesh
fc9c9ab22d [PATCH] AYSNC IO using singals other than SIGIO
A question on sigwaitinfo based IO mechanism in multithreaded applications.

I am trying to use RT signals to notify me of IO events using RT signals
instead of SIGIO in a multithreaded applications.  I noticed that there was
some discussion on lkml during november 1999 with the subject of the
discussion as "Signal driven IO".  In the thread I noticed that RT signals
were being delivered to the worker thread.  I am running 2.6.10 kernel and
I am trying to use the very same mechanism and I find that only SIGIO being
propogated to the worker threads and RT signals only being propogated to
the main thread and not the worker threads where I actually want them to be
propogated too.  On further inspection I found that the following patch
which I have attached solves the problem.

I am not sure if this is a bug or feature in the kernel.


Roland McGrath <roland@redhat.com> said:

This relates only to fcntl F_SETSIG, which is a Linux extension.  So there is
no POSIX issue.  When changing various things like the normal SIGIO signalling
to do group signals, I was concerned strictly with the POSIX semantics and
generally avoided touching things in the domain of Linux inventions.  That's
why I didn't change this when I changed the call right next to it.  There is
no reason I can see that F_SETSIG-requested signals shouldn't use a group
signal like normal SIGIO does.  I'm happy to ACK this patch, there is nothing
wrong with its change to the semantics in my book.  But neither POSIX nor I
care a whit what F_SETSIG does.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16 15:25:41 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00