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locks: report l_pid as -1 for FL_FILE_PVT locks

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FL_FILE_PVT locks are no longer tied to a particular pid, and are
instead inheritable by child processes. Report a l_pid of '-1' for
these sorts of locks since the pid is somewhat meaningless for them.

This precedent comes from FreeBSD. There, POSIX and flock() locks can
conflict with one another. If fcntl(F_GETLK, ...) returns a lock set
with flock() then the l_pid member cannot be a process ID because the
lock is not held by a process as such.

Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
This commit is contained in:
Jeff Layton 2014-02-03 12:13:09 -05:00
parent c918d42a27
commit 3fd80cddc6
1 changed files with 2 additions and 2 deletions
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4
fs/locks.c
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@ -1864,7 +1864,7 @@ EXPORT_SYMBOL_GPL(vfs_test_lock);
static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
{
flock->l_pid = fl->fl_pid;
flock->l_pid = IS_FILE_PVT(fl) ? -1 : fl->fl_pid;
#if BITS_PER_LONG == 32
/*
* Make sure we can represent the posix lock via
@ -1886,7 +1886,7 @@ static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
#if BITS_PER_LONG == 32
static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
{
flock->l_pid = fl->fl_pid;
flock->l_pid = IS_FILE_PVT(fl) ? -1 : fl->fl_pid;
flock->l_start = fl->fl_start;
flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
fl->fl_end - fl->fl_start + 1;