From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
John Sullivan <jsrhbz@kanargh.force9.co.uk>,
"Theodore Tso" <tytso@mit.edu>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 3.13 01/22] ext4: atomically set inode->i_flags in ext4_set_inode_flags()
Date: Mon, 31 Mar 2014 21:08:31 -0700 [thread overview]
Message-ID: <20140401040703.320575581@linuxfoundation.org> (raw)
In-Reply-To: <20140401040703.045139933@linuxfoundation.org>
3.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Theodore Ts'o <tytso@mit.edu>
commit 00a1a053ebe5febcfc2ec498bd894f035ad2aa06 upstream.
Use cmpxchg() to atomically set i_flags instead of clearing out the
S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the
EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race
where an immutable file has the immutable flag cleared for a brief
window of time.
Reported-by: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ext4/inode.c | 15 +++++++++------
include/linux/bitops.h | 15 +++++++++++++++
2 files changed, 24 insertions(+), 6 deletions(-)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -38,6 +38,7 @@
#include <linux/slab.h>
#include <linux/ratelimit.h>
#include <linux/aio.h>
+#include <linux/bitops.h>
#include "ext4_jbd2.h"
#include "xattr.h"
@@ -3926,18 +3927,20 @@ int ext4_get_inode_loc(struct inode *ino
void ext4_set_inode_flags(struct inode *inode)
{
unsigned int flags = EXT4_I(inode)->i_flags;
+ unsigned int new_fl = 0;
- inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
if (flags & EXT4_SYNC_FL)
- inode->i_flags |= S_SYNC;
+ new_fl |= S_SYNC;
if (flags & EXT4_APPEND_FL)
- inode->i_flags |= S_APPEND;
+ new_fl |= S_APPEND;
if (flags & EXT4_IMMUTABLE_FL)
- inode->i_flags |= S_IMMUTABLE;
+ new_fl |= S_IMMUTABLE;
if (flags & EXT4_NOATIME_FL)
- inode->i_flags |= S_NOATIME;
+ new_fl |= S_NOATIME;
if (flags & EXT4_DIRSYNC_FL)
- inode->i_flags |= S_DIRSYNC;
+ new_fl |= S_DIRSYNC;
+ set_mask_bits(&inode->i_flags,
+ S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC, new_fl);
}
/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -196,6 +196,21 @@ static inline unsigned long __ffs64(u64
#ifdef __KERNEL__
+#ifndef set_mask_bits
+#define set_mask_bits(ptr, _mask, _bits) \
+({ \
+ const typeof(*ptr) mask = (_mask), bits = (_bits); \
+ typeof(*ptr) old, new; \
+ \
+ do { \
+ old = ACCESS_ONCE(*ptr); \
+ new = (old & ~mask) | bits; \
+ } while (cmpxchg(ptr, old, new) != old); \
+ \
+ new; \
+})
+#endif
+
#ifndef find_last_bit
/**
* find_last_bit - find the last set bit in a memory region
next prev parent reply other threads:[~2014-04-01 4:08 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-01 4:08 [PATCH 3.13 00/22] 3.13.9-stable review Greg Kroah-Hartman
2014-04-01 4:08 ` Greg Kroah-Hartman [this message]
2014-04-01 4:08 ` [PATCH 3.13 02/22] rcuwalk: recheck mount_lock after mountpoint crossing attempts Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 03/22] Input: mousedev - fix race when creating mixed device Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 04/22] Input: synaptics - add manual min/max quirk Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 05/22] Input: synaptics - add manual min/max quirk for ThinkPad X240 Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 06/22] Input: cypress_ps2 - dont report as a button pads Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 07/22] xen/balloon: flush persistent kmaps in correct position Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 08/22] Revert "xen: properly account for _PAGE_NUMA during xen pte translations" Greg Kroah-Hartman
2014-04-10 10:05 ` Steven Noonan
2014-04-10 10:08 ` David Vrabel
2014-04-01 4:08 ` [PATCH 3.13 09/22] i2c: cpm: Fix build by adding of_address.h and of_irq.h Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 10/22] drm/i915: Undo gtt scratch pte unmapping again Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 11/22] x86: fix boot on uniprocessor systems Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 12/22] make prepend_name() work correctly when called with negative *buflen Greg Kroah-Hartman
2014-04-09 20:17 ` Sasha Levin
2014-04-01 4:08 ` [PATCH 3.13 13/22] net: mvneta: rename MVNETA_GMAC2_PSC_ENABLE to MVNETA_GMAC2_PCS_ENABLE Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 14/22] net: mvneta: fix usage as a module on RGMII configurations Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 15/22] random32: avoid attempt to late reseed if in the middle of seeding Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 16/22] resizable namespace.c hashes Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 17/22] keep shadowed vfsmounts together Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 18/22] dont bother with propagate_mnt() unless the target is shared Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 19/22] switch mnt_hash to hlist Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 20/22] mm: close PageTail race Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 21/22] cgroup: protect modifications to cgroup_idr with cgroup_mutex Greg Kroah-Hartman
2014-04-01 4:08 ` [PATCH 3.13 22/22] netfilter: nf_conntrack_dccp: fix skb_header_pointer API usages Greg Kroah-Hartman
2014-04-02 0:03 ` [PATCH 3.13 00/22] 3.13.9-stable review Guenter Roeck
2014-04-03 22:45 ` Greg Kroah-Hartman
2014-04-04 13:30 ` Shuah Khan
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