linux.git/fs/compat.c, branch v4.6

saner calling conventions for copy_mount_options()

2016-01-04T15:28:32+00:00

let it just return NULL, pointer to kernel copy or ERR_PTR().

Signed-off-by: Al Viro

vfs: make first argument of dir_context.actor typed

2014-10-31T21:48:54+00:00

Signed-off-by: Miklos Szeredi 
Signed-off-by: Al Viro

vfs: move getname() from callers to do_mount()

2014-10-09T06:39:16+00:00

It would make more sense to pass char __user * instead of
char * in callers of do_mount() and do getname() inside do_mount().

Suggested-by: Al Viro 
Signed-off-by: Seunghun Lee 
Signed-off-by: Al Viro

fs: namespace: suppress 'may be used uninitialized' warnings

2014-10-09T06:39:10+00:00

The gcc version 4.9.1 compiler complains Even though it isn't possible for
these variables to not get initialized before they are used.

fs/namespace.c: In function ‘SyS_mount’:
fs/namespace.c:2720:8: warning: ‘kernel_dev’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  ret = do_mount(kernel_dev, kernel_dir->name, kernel_type, flags,
        ^
fs/namespace.c:2699:8: note: ‘kernel_dev’ was declared here
  char *kernel_dev;
        ^
fs/namespace.c:2720:8: warning: ‘kernel_type’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  ret = do_mount(kernel_dev, kernel_dir->name, kernel_type, flags,
        ^
fs/namespace.c:2697:8: note: ‘kernel_type’ was declared here
  char *kernel_type;
        ^

Fix the warnings by simplifying copy_mount_string() as suggested by Al Viro.

Cc: Alexander Viro 
Signed-off-by: Tim Gardner 
Signed-off-by: Al Viro

locks: rename file-private locks to "open file description locks"

2014-04-22T12:23:58+00:00

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 
Cc: Christoph Hellwig 
Cc: Carlos O'Donell 
Cc: Stefan Metzmacher 
Cc: Andy Lutomirski 
Cc: Frank Filz 
Cc: Theodore Ts'o 
Signed-off-by: Jeff Layton

Merge branch 'locks-3.15' of git://git.samba.org/jlayton/linux

2014-04-04T21:21:20+00:00

Pull file locking updates from Jeff Layton:
 "Highlights:

   - maintainership change for fs/locks.c.  Willy's not interested in
     maintaining it these days, and is OK with Bruce and I taking it.
   - fix for open vs setlease race that Al ID'ed
   - cleanup and consolidation of file locking code
   - eliminate unneeded BUG() call
   - merge of file-private lock implementation"

* 'locks-3.15' of git://git.samba.org/jlayton/linux:
  locks: make locks_mandatory_area check for file-private locks
  locks: fix locks_mandatory_locked to respect file-private locks
  locks: require that flock->l_pid be set to 0 for file-private locks
  locks: add new fcntl cmd values for handling file private locks
  locks: skip deadlock detection on FL_FILE_PVT locks
  locks: pass the cmd value to fcntl_getlk/getlk64
  locks: report l_pid as -1 for FL_FILE_PVT locks
  locks: make /proc/locks show IS_FILE_PVT locks as type "FLPVT"
  locks: rename locks_remove_flock to locks_remove_file
  locks: consolidate checks for compatible filp->f_mode values in setlk handlers
  locks: fix posix lock range overflow handling
  locks: eliminate BUG() call when there's an unexpected lock on file close
  locks: add __acquires and __releases annotations to locks_start and locks_stop
  locks: remove "inline" qualifier from fl_link manipulation functions
  locks: clean up comment typo
  locks: close potential race between setlease and open
  MAINTAINERS: update entry for fs/locks.c

Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-04-02T19:51:41+00:00

Pull compat time conversion changes from Peter Anvin:
 "Despite the branch name this is really neither an x86 nor an
  x32-specific patchset, although it the implementation of the
  discussions that followed the x32 security hole a few months ago.

  This removes get/put_compat_timespec/val() and replaces them with
  compat_get/put_timespec/val() which are savvy as to the current status
  of COMPAT_USE_64BIT_TIME.

  It removes several unused and/or incorrect/misleading functions (like
  compat_put_timeval_convert which doesn't in fact do any conversion)
  and also replaces several open-coded implementations what is now
  called compat_convert_timespec() with that function"

* 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  compat: Fix sparse address space warnings
  compat: Get rid of (get|put)_compat_time(val|spec)

locks: add new fcntl cmd values for handling file private locks

2014-03-31T12:24:43+00:00

Due to some unfortunate history, POSIX locks have very strange and
unhelpful semantics. The thing that usually catches people by surprise
is that they are dropped whenever the process closes any file descriptor
associated with the inode.

This is extremely problematic for people developing file servers that
need to implement byte-range locks. Developers often need a "lock
management" facility to ensure that file descriptors are not closed
until all of the locks associated with the inode are finished.

Additionally, "classic" POSIX locks are owned by the process. Locks
taken between threads within the same process won't conflict with one
another, which renders them useless for synchronization between threads.

This patchset adds a new type of lock that attempts to address these
issues. These locks conflict with classic POSIX read/write locks, but
have semantics that are more like BSD locks with respect to inheritance
and behavior on close.

This is implemented primarily by changing how fl_owner field is set for
these locks. Instead of having them owned by the files_struct of the
process, they are instead owned by the filp on which they were acquired.
Thus, they are inherited across fork() and are only released when the
last reference to a filp is put.

These new semantics prevent them from being merged with classic POSIX
locks, even if they are acquired by the same process. These locks will
also conflict with classic POSIX locks even if they are acquired by
the same process or on the same file descriptor.

The new locks are managed using a new set of cmd values to the fcntl()
syscall. The initial implementation of this converts these values to
"classic" cmd values at a fairly high level, and the details are not
exposed to the underlying filesystem. We may eventually want to push
this handing out to the lower filesystem code but for now I don't
see any need for it.

Also, note that with this implementation the new cmd values are only
available via fcntl64() on 32-bit arches. There's little need to
add support for legacy apps on a new interface like this.

Signed-off-by: Jeff Layton

fs/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types

2014-03-06T15:30:44+00:00

Some fs compat system calls have unsigned long parameters instead of
compat_ulong_t.
In order to allow the COMPAT_SYSCALL_DEFINE macro generate code that
performs proper zero and sign extension convert all 64 bit parameters
their corresponding 32 bit counterparts.

compat_sys_io_getevents() is a bit different: the non-compat version
has signed parameters for the "min_nr" and "nr" parameters while the
compat version has unsigned parameters.
So change this as well. For all practical purposes this shouldn't make
any difference (doesn't fix a real bug).
Also introduce a generic compat_aio_context_t type which can be used
everywhere.
The access_ok() check within compat_sys_io_getevents() got also removed
since the non-compat sys_io_getevents() should be able to handle
everything anyway.

Signed-off-by: Heiko Carstens

fs/compat: convert to COMPAT_SYSCALL_DEFINE

2014-03-06T15:30:43+00:00

Convert all compat system call functions where all parameter types
have a size of four or less than four bytes, or are pointer types
to COMPAT_SYSCALL_DEFINE.
The implicit casts within COMPAT_SYSCALL_DEFINE will perform proper
zero and sign extension to 64 bit of all parameters if needed.

Signed-off-by: Heiko Carstens