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/*
* Copyright (C) 2005-2015 Junjiro R. Okajima
*
* This program, aufs is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* poll operation
* There is only one filesystem which implements ->poll operation, currently.
*/
#include "aufs.h"
unsigned int aufs_poll(struct file *file, poll_table *wait)
{
unsigned int mask;
int err;
struct file *h_file;
struct super_block *sb;
/* We should pretend an error happened. */
mask = POLLERR /* | POLLIN | POLLOUT */;
sb = file->f_path.dentry->d_sb;
si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
h_file = au_read_pre(file, /*keep_fi*/0);
err = PTR_ERR(h_file);
if (IS_ERR(h_file))
goto out;
/* it is not an error if h_file has no operation */
mask = DEFAULT_POLLMASK;
if (h_file->f_op->poll)
mask = h_file->f_op->poll(h_file, wait);
fput(h_file); /* instead of au_read_post() */
out:
si_read_unlock(sb);
AuTraceErr((int)mask);
return mask;
}
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