[XFS] Really fix use after free in xfs_iunpin.
The previous attempts to fix the linux inode use-after-free in xfs_iunpin
simply made the problem harder to hit. We actually need complete exclusion
between xfs_reclaim and xfs_iunpin, as well as ensuring that the i_flags
are consistent during both of these functions. Introduce a new spinlock
for exclusion and the i_flags, and fix up xfs_iunpin to use igrab before
marking the inode dirty.
SGI-PV: 952967
SGI-Modid: xfs-linux-melb:xfs-kern:26964a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 9df9ed3..38c4d12 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -227,7 +227,9 @@
xfs_revalidate_inode(XFS_BHVTOM(bdp), vp, ip);
xfs_set_inodeops(inode);
+ spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~XFS_INEW;
+ spin_unlock(&ip->i_flags_lock);
barrier();
unlock_new_inode(inode);
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index 9b93797..b73d216 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -243,7 +243,9 @@
XFS_STATS_INC(xs_ig_found);
+ spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~XFS_IRECLAIMABLE;
+ spin_unlock(&ip->i_flags_lock);
version = ih->ih_version;
read_unlock(&ih->ih_lock);
xfs_ihash_promote(ih, ip, version);
@@ -297,7 +299,9 @@
if (lock_flags != 0)
xfs_ilock(ip, lock_flags);
+ spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~XFS_ISTALE;
+ spin_unlock(&ip->i_flags_lock);
vn_trace_exit(vp, "xfs_iget.found",
(inst_t *)__return_address);
@@ -367,7 +371,9 @@
ih->ih_next = ip;
ip->i_udquot = ip->i_gdquot = NULL;
ih->ih_version++;
+ spin_lock(&ip->i_flags_lock);
ip->i_flags |= XFS_INEW;
+ spin_unlock(&ip->i_flags_lock);
write_unlock(&ih->ih_lock);
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 66a7828..c27d7d49 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -867,6 +867,7 @@
ip = kmem_zone_zalloc(xfs_inode_zone, KM_SLEEP);
ip->i_ino = ino;
ip->i_mount = mp;
+ spin_lock_init(&ip->i_flags_lock);
/*
* Get pointer's to the on-disk inode and the buffer containing it.
@@ -2214,7 +2215,9 @@
if (ip == free_ip) {
if (xfs_iflock_nowait(ip)) {
+ spin_lock(&ip->i_flags_lock);
ip->i_flags |= XFS_ISTALE;
+ spin_unlock(&ip->i_flags_lock);
if (xfs_inode_clean(ip)) {
xfs_ifunlock(ip);
@@ -2228,7 +2231,9 @@
if (xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) {
if (xfs_iflock_nowait(ip)) {
+ spin_lock(&ip->i_flags_lock);
ip->i_flags |= XFS_ISTALE;
+ spin_unlock(&ip->i_flags_lock);
if (xfs_inode_clean(ip)) {
xfs_ifunlock(ip);
@@ -2258,7 +2263,9 @@
AIL_LOCK(mp,s);
iip->ili_flush_lsn = iip->ili_item.li_lsn;
AIL_UNLOCK(mp, s);
+ spin_lock(&iip->ili_inode->i_flags_lock);
iip->ili_inode->i_flags |= XFS_ISTALE;
+ spin_unlock(&iip->ili_inode->i_flags_lock);
pre_flushed++;
}
lip = lip->li_bio_list;
@@ -2754,19 +2761,29 @@
* call as the inode reclaim may be blocked waiting for
* the inode to become unpinned.
*/
+ struct inode *inode = NULL;
+
+ spin_lock(&ip->i_flags_lock);
if (!(ip->i_flags & (XFS_IRECLAIM|XFS_IRECLAIMABLE))) {
bhv_vnode_t *vp = XFS_ITOV_NULL(ip);
/* make sync come back and flush this inode */
if (vp) {
- struct inode *inode = vn_to_inode(vp);
+ inode = vn_to_inode(vp);
if (!(inode->i_state &
- (I_NEW|I_FREEING|I_CLEAR)))
- mark_inode_dirty_sync(inode);
+ (I_NEW|I_FREEING|I_CLEAR))) {
+ inode = igrab(inode);
+ if (inode)
+ mark_inode_dirty_sync(inode);
+ } else
+ inode = NULL;
}
}
+ spin_unlock(&ip->i_flags_lock);
wake_up(&ip->i_ipin_wait);
+ if (inode)
+ iput(inode);
}
}
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index fdb89f7..e96eb08 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -267,6 +267,7 @@
sema_t i_flock; /* inode flush lock */
atomic_t i_pincount; /* inode pin count */
wait_queue_head_t i_ipin_wait; /* inode pinning wait queue */
+ spinlock_t i_flags_lock; /* inode i_flags lock */
#ifdef HAVE_REFCACHE
struct xfs_inode **i_refcache; /* ptr to entry in ref cache */
struct xfs_inode *i_release; /* inode to unref */
diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index b608b8a..136c6b0 100644
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -577,6 +577,7 @@
KM_SLEEP);
ip->i_ino = ino;
ip->i_mount = mp;
+ spin_lock_init(&ip->i_flags_lock);
if (bp)
xfs_buf_relse(bp);
error = xfs_itobp(mp, NULL, ip,
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 1a6782e..061e2ff 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -3844,7 +3844,9 @@
XFS_MOUNT_ILOCK(mp);
vn_bhv_remove(VN_BHV_HEAD(vp), XFS_ITOBHV(ip));
list_add_tail(&ip->i_reclaim, &mp->m_del_inodes);
+ spin_lock(&ip->i_flags_lock);
ip->i_flags |= XFS_IRECLAIMABLE;
+ spin_unlock(&ip->i_flags_lock);
XFS_MOUNT_IUNLOCK(mp);
}
return 0;
@@ -3869,8 +3871,10 @@
* us.
*/
write_lock(&ih->ih_lock);
+ spin_lock(&ip->i_flags_lock);
if ((ip->i_flags & XFS_IRECLAIM) ||
(!(ip->i_flags & XFS_IRECLAIMABLE) && vp == NULL)) {
+ spin_unlock(&ip->i_flags_lock);
write_unlock(&ih->ih_lock);
if (locked) {
xfs_ifunlock(ip);
@@ -3879,6 +3883,7 @@
return 1;
}
ip->i_flags |= XFS_IRECLAIM;
+ spin_unlock(&ip->i_flags_lock);
write_unlock(&ih->ih_lock);
/*