linux.git/include/asm-generic/fcntl.h, branch master

UAPI: (Scripted) Disintegrate include/asm-generic

2012-10-04T17:20:15+00:00

Signed-off-by: David Howells 
Acked-by: Arnd Bergmann 
Acked-by: Thomas Gleixner 
Acked-by: Michael Kerrisk 
Acked-by: Paul E. McKenney 
Acked-by: Dave Jones

c/r: fcntl: add F_GETOWNER_UIDS option

2012-07-31T00:25:21+00:00

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 
Acked-by: "Eric W. Biederman" 
Cc: "Serge E. Hallyn" 
Cc: Oleg Nesterov 
Cc: Pavel Emelyanov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

locks: move F_INPROGRESS from fl_type to fl_flags field

2011-08-19T17:25:34+00:00

F_INPROGRESS isn't exposed to userspace.  To me it makes more sense in
fl_flags....

Reviewed-by: Jeff Layton 
Signed-off-by: J. Bruce Fields

New kind of open files - "location only".

2011-03-15T06:21:45+00:00

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

asm-generic: fcntl: make exported headers use strict posix types

2010-10-09T19:51:43+00:00

All 'pid_t' were changed to '__kernel_pid_t' in a previous commit:
make exported headers use strict posix types

    A number of standard posix types are used in exported headers,
    which is not allowed if __STRICT_KERNEL_NAMES is defined. In order
    to get rid of the non-__STRICT_KERNEL_NAMES part and to make sane
    headers the default, we have to change them all to safe types.

but a later change introduced 'pid_t' again:
    fcntl: add F_[SG]ETOWN_EX

This makes asm-generic/fcntl.h d use strict posix types again.

Signed-off-by: Lucian Adrian Grijincu 
Signed-off-by: Andrew Morton 
Signed-off-by: Arnd Bergmann

vfs: O_* bit numbers uniqueness check

2010-08-11T15:59:02+00:00

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 
Cc: David Miller 
Cc: Stephen Rothwell 
Cc: Al Viro 
Cc: Christoph Hellwig 
Cc: Eric Paris 
Cc: Roland Dreier 
Cc: Jamie Lokier 
Cc: Andreas Schwab 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fanotify: FMODE_NONOTIFY and __O_SYNC in sparc conflict

2010-07-28T13:58:54+00:00

sparc used the same value as FMODE_NONOTIFY so change FMODE_NONOTIFY to be
something unique.

Signed-off-by: Wu Fengguang 
Signed-off-by: Eric Paris

vfs: introduce FMODE_NONOTIFY

2010-07-28T13:58:54+00:00

This is a new f_mode which can only be set by the kernel.  It indicates
that the fd was opened by fanotify and should not cause future fanotify
events.  This is needed to prevent fanotify livelock.  An example of
obvious livelock is from fanotify close events.

Process A closes file1
This creates a close event for file1.
fanotify opens file1 for Listener X
Listener X deals with the event and closes its fd for file1.
This creates a close event for file1.
fanotify opens file1 for Listener X
Listener X deals with the event and closes its fd for file1.
This creates a close event for file1.
fanotify opens file1 for Listener X
Listener X deals with the event and closes its fd for file1.
notice a pattern?

The fix is to add the FMODE_NONOTIFY bit to the open filp done by the kernel
for fanotify.  Thus when that file is used it will not generate future
events.

This patch simply defines the bit.

Signed-off-by: Eric Paris

fix up O_SYNC comments

2009-12-17T16:03:24+00:00

Proper Posix O_SYNC handling only made it into 2.6.33, not 2.6.32.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

vfs: Implement proper O_SYNC semantics

2009-12-10T14:02:50+00:00

While Linux provided an O_SYNC flag basically since day 1, it took until
Linux 2.4.0-test12pre2 to actually get it implemented for filesystems,
since that day we had generic_osync_around with only minor changes and the
great "For now, when the user asks for O_SYNC, we'll actually give
O_DSYNC" comment.  This patch intends to actually give us real O_SYNC
semantics in addition to the O_DSYNC semantics.  After Jan's O_SYNC
patches which are required before this patch it's actually surprisingly
simple, we just need to figure out when to set the datasync flag to
vfs_fsync_range and when not.

This patch renames the existing O_SYNC flag to O_DSYNC while keeping it's
numerical value to keep binary compatibility, and adds a new real O_SYNC
flag.  To guarantee backwards compatiblity it is defined as expanding to
both the O_DSYNC and the new additional binary flag (__O_SYNC) to make
sure we are backwards-compatible when compiled against the new headers.

This also means that all places that don't care about the differences can
just check O_DSYNC and get the right behaviour for O_SYNC, too - only
places that actuall care need to check __O_SYNC in addition.  Drivers and
network filesystems have been updated in a fail safe way to always do the
full sync magic if O_DSYNC is set.  The few places setting O_SYNC for
lower layers are kept that way for now to stay failsafe.

We enforce that O_DSYNC is set when __O_SYNC is set early in the open path
to make sure we always get these sane options.

Note that parisc really screwed up their headers as they already define a
O_DSYNC that has always been a no-op.  We try to repair it by using it for
the new O_DSYNC and redefinining O_SYNC to send both the traditional
O_SYNC numerical value _and_ the O_DSYNC one.

Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Grant Grundler 
Cc: "David S. Miller" 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Thomas Gleixner 
Cc: Al Viro 
Cc: Andreas Dilger 
Acked-by: Trond Myklebust 
Acked-by: Kyle McMartin 
Acked-by: Ulrich Drepper 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Jan Kara