/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * xattr.h
 *
 * Copyright (C) 2004, 2008 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License version 2 as published by the Free Software Foundation.
 *
 * 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.
 */

#ifndef OCFS2_XATTR_H
#define OCFS2_XATTR_H

#include <linux/init.h>
#include <linux/xattr.h>

enum ocfs2_xattr_type {
	OCFS2_XATTR_INDEX_USER = 1,
	OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS,
	OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT,
	OCFS2_XATTR_INDEX_TRUSTED,
	OCFS2_XATTR_INDEX_SECURITY,
	OCFS2_XATTR_MAX
};

struct ocfs2_security_xattr_info {
	int enable;
	const char *name;
	void *value;
	size_t value_len;
};

extern const struct xattr_handler ocfs2_xattr_user_handler;
extern const struct xattr_handler ocfs2_xattr_trusted_handler;
extern const struct xattr_handler ocfs2_xattr_security_handler;
extern const struct xattr_handler *ocfs2_xattr_handlers[];

ssize_t ocfs2_listxattr(struct dentry *, char *, size_t);
int ocfs2_xattr_get_nolock(struct inode *, struct buffer_head *, int,
			   const char *, void *, size_t);
int ocfs2_xattr_set(struct inode *, int, const char *, const void *,
		    size_t, int);
int ocfs2_xattr_set_handle(handle_t *, struct inode *, struct buffer_head *,
			   int, const char *, const void *, size_t, int,
			   struct ocfs2_alloc_context *,
			   struct ocfs2_alloc_context *);
int ocfs2_has_inline_xattr_value_outside(struct inode *inode,
					 struct ocfs2_dinode *di);
int ocfs2_xattr_remove(struct inode *, struct buffer_head *);
int ocfs2_init_security_get(struct inode *, struct inode *,
			    const struct qstr *,
			    struct ocfs2_security_xattr_info *);
int ocfs2_init_security_set(handle_t *, struct inode *,
			    struct buffer_head *,
			    struct ocfs2_security_xattr_info *,
			    struct ocfs2_alloc_context *,
			    struct ocfs2_alloc_context *);
int ocfs2_calc_security_init(struct inode *,
			     struct ocfs2_security_xattr_info *,
			     int *, int *, struct ocfs2_alloc_context **);
int ocfs2_calc_xattr_init(struct inode *, struct buffer_head *,
			  umode_t, struct ocfs2_security_xattr_info *,
			  int *, int *, int *);

/*
 * xattrs can live inside an inode, as part of an external xattr block,
 * or inside an xattr bucket, which is the leaf of a tree rooted in an
 * xattr block.  Some of the xattr calls, especially the value setting
 * functions, want to treat each of these locations as equal.  Let's wrap
 * them in a structure that we can pass around instead of raw buffer_heads.
 */
struct ocfs2_xattr_value_buf {
	struct buffer_head		*vb_bh;
	ocfs2_journal_access_func	vb_access;
	struct ocfs2_xattr_value_root	*vb_xv;
};

int ocfs2_xattr_attach_refcount_tree(struct inode *inode,
				     struct buffer_head *fe_bh,
				     struct ocfs2_caching_info *ref_ci,
				     struct buffer_head *ref_root_bh,
				     struct ocfs2_cached_dealloc_ctxt *dealloc);
int ocfs2_reflink_xattrs(struct inode *old_inode,
			 struct buffer_head *old_bh,
			 struct inode *new_inode,
			 struct buffer_head *new_bh,
			 bool preserve_security);
int ocfs2_init_security_and_acl(struct inode *dir,
				struct inode *inode,
				const struct qstr *qstr);
#endif /* OCFS2_XATTR_H */
ext.git/log/fs/btrfs/print-tree.h?h=nds-private-remove&amp;id=2cbf5b4212b1595449548f189a8fb2df0b25a03f&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Douglas Miller &lt;dougmill@linux.vnet.ibm.com&gt;</td><td class='right'>2017-01-28 06:42:20 -0600</td></tr>
<tr><th>committer</th><td>Tejun Heo &lt;tj@kernel.org&gt;</td><td class='right'>2017-01-28 07:49:42 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/security/keys/Makefile?id=966d2b04e070bc040319aaebfec09e0144dc3341'>966d2b04e070bc040319aaebfec09e0144dc3341</a> (<a href='/cgit.cgi/linux/net-next.git/patch/security/keys/Makefile?id=966d2b04e070bc040319aaebfec09e0144dc3341'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>4b96156e3d1dd4dfd6039b7c219c9dc4616da52d</a> /<a href='/cgit.cgi/linux/net-next.git/tree/security/keys/Makefile?id=966d2b04e070bc040319aaebfec09e0144dc3341'>security/keys/Makefile</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/security/keys/Makefile?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>1b1bc42c1692e9b62756323c675a44cb1a1f9dbd</a> (<a href='/cgit.cgi/linux/net-next.git/diff/security/keys/Makefile?id=966d2b04e070bc040319aaebfec09e0144dc3341&amp;id2=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>diff</a>)</td></tr></table>
<div class='commit-subject'>percpu-refcount: fix reference leak during percpu-atomic transition</div><div class='commit-msg'>percpu_ref_tryget() and percpu_ref_tryget_live() should return
"true" IFF they acquire a reference. But the return value from
atomic_long_inc_not_zero() is a long and may have high bits set,
e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines
is bool so the reference may actually be acquired but the routines
return "false" which results in a reference leak since the caller
assumes it does not need to do a corresponding percpu_ref_put().

This was seen when performing CPU hotplug during I/O, as hangs in
blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start)
raced with percpu_ref_tryget (blk_mq_timeout_work).
Sample stack trace:

__switch_to+0x2c0/0x450
__schedule+0x2f8/0x970
schedule+0x48/0xc0
blk_mq_freeze_queue_wait+0x94/0x120
blk_mq_queue_reinit_work+0xb8/0x180
blk_mq_queue_reinit_prepare+0x84/0xa0
cpuhp_invoke_callback+0x17c/0x600
cpuhp_up_callbacks+0x58/0x150
_cpu_up+0xf0/0x1c0
do_cpu_up+0x120/0x150
cpu_subsys_online+0x64/0xe0
device_online+0xb4/0x120
online_store+0xb4/0xc0
dev_attr_store+0x68/0xa0
sysfs_kf_write+0x80/0xb0
kernfs_fop_write+0x17c/0x250
__vfs_write+0x6c/0x1e0
vfs_write+0xd0/0x270
SyS_write+0x6c/0x110
system_call+0x38/0xe0

Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS,
and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests.
However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0
and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set.

The fix is to make the tryget routines use an actual boolean internally instead
of the atomic long result truncated to a int.

Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints
Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751
Signed-off-by: Douglas Miller &lt;dougmill@linux.vnet.ibm.com&gt;
Reviewed-by: Jens Axboe &lt;axboe@fb.com&gt;
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints")
Cc: stable@vger.kernel.org # v3.18+
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=966d2b04e070bc040319aaebfec09e0144dc3341'>Diffstat</a> (limited to 'security/keys/Makefile')</div><table summary='diffstat' class='diffstat'>