Merge branch 'master' into for-linus-merged
This merge pulls the XFS master branch into the latest Linus master.
This results in a merge conflict whose best fix is not obvious.
I manually fixed the conflict, in "fs/xfs/xfs_iget.c".
Dave Chinner had done work that resulted in RCU freeing of inodes
separate from what Nick Piggin had done, and their results differed
slightly in xfs_inode_free(). The fix updates Nick's call_rcu()
with the use of VFS_I(), while incorporating needed updates to some
XFS inode fields implemented in Dave's series. Dave's RCU callback
function has also been removed.
Signed-off-by: Alex Elder <aelder@sgi.com>
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index d7de5a3..cb9b6d1 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -43,6 +43,17 @@
/*
+ * Define xfs inode iolock lockdep classes. We need to ensure that all active
+ * inodes are considered the same for lockdep purposes, including inodes that
+ * are recycled through the XFS_IRECLAIMABLE state. This is the the only way to
+ * guarantee the locks are considered the same when there are multiple lock
+ * initialisation siteѕ. Also, define a reclaimable inode class so it is
+ * obvious in lockdep reports which class the report is against.
+ */
+static struct lock_class_key xfs_iolock_active;
+struct lock_class_key xfs_iolock_reclaimable;
+
+/*
* Allocate and initialise an xfs_inode.
*/
STATIC struct xfs_inode *
@@ -69,8 +80,11 @@
ASSERT(atomic_read(&ip->i_pincount) == 0);
ASSERT(!spin_is_locked(&ip->i_flags_lock));
ASSERT(completion_done(&ip->i_flush));
+ ASSERT(ip->i_ino == 0);
mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+ lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
+ &xfs_iolock_active, "xfs_iolock_active");
/* initialise the xfs inode */
ip->i_ino = ino;
@@ -85,9 +99,6 @@
ip->i_size = 0;
ip->i_new_size = 0;
- /* prevent anyone from using this yet */
- VFS_I(ip)->i_state = I_NEW;
-
return ip;
}
@@ -145,7 +156,18 @@
ASSERT(!spin_is_locked(&ip->i_flags_lock));
ASSERT(completion_done(&ip->i_flush));
- call_rcu(&ip->i_vnode.i_rcu, xfs_inode_free_callback);
+ /*
+ * Because we use RCU freeing we need to ensure the inode always
+ * appears to be reclaimed with an invalid inode number when in the
+ * free state. The ip->i_flags_lock provides the barrier against lookup
+ * races.
+ */
+ spin_lock(&ip->i_flags_lock);
+ ip->i_flags = XFS_IRECLAIM;
+ ip->i_ino = 0;
+ spin_unlock(&ip->i_flags_lock);
+
+ call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
}
/*
@@ -155,14 +177,29 @@
xfs_iget_cache_hit(
struct xfs_perag *pag,
struct xfs_inode *ip,
+ xfs_ino_t ino,
int flags,
- int lock_flags) __releases(pag->pag_ici_lock)
+ int lock_flags) __releases(RCU)
{
struct inode *inode = VFS_I(ip);
struct xfs_mount *mp = ip->i_mount;
int error;
+ /*
+ * check for re-use of an inode within an RCU grace period due to the
+ * radix tree nodes not being updated yet. We monitor for this by
+ * setting the inode number to zero before freeing the inode structure.
+ * If the inode has been reallocated and set up, then the inode number
+ * will not match, so check for that, too.
+ */
spin_lock(&ip->i_flags_lock);
+ if (ip->i_ino != ino) {
+ trace_xfs_iget_skip(ip);
+ XFS_STATS_INC(xs_ig_frecycle);
+ error = EAGAIN;
+ goto out_error;
+ }
+
/*
* If we are racing with another cache hit that is currently
@@ -205,7 +242,7 @@
ip->i_flags |= XFS_IRECLAIM;
spin_unlock(&ip->i_flags_lock);
- read_unlock(&pag->pag_ici_lock);
+ rcu_read_unlock();
error = -inode_init_always(mp->m_super, inode);
if (error) {
@@ -213,7 +250,7 @@
* Re-initializing the inode failed, and we are in deep
* trouble. Try to re-add it to the reclaim list.
*/
- read_lock(&pag->pag_ici_lock);
+ rcu_read_lock();
spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~XFS_INEW;
@@ -223,14 +260,20 @@
goto out_error;
}
- write_lock(&pag->pag_ici_lock);
+ spin_lock(&pag->pag_ici_lock);
spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~(XFS_IRECLAIMABLE | XFS_IRECLAIM);
ip->i_flags |= XFS_INEW;
__xfs_inode_clear_reclaim_tag(mp, pag, ip);
inode->i_state = I_NEW;
+
+ ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
+ mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+ lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
+ &xfs_iolock_active, "xfs_iolock_active");
+
spin_unlock(&ip->i_flags_lock);
- write_unlock(&pag->pag_ici_lock);
+ spin_unlock(&pag->pag_ici_lock);
} else {
/* If the VFS inode is being torn down, pause and try again. */
if (!igrab(inode)) {
@@ -241,7 +284,7 @@
/* We've got a live one. */
spin_unlock(&ip->i_flags_lock);
- read_unlock(&pag->pag_ici_lock);
+ rcu_read_unlock();
trace_xfs_iget_hit(ip);
}
@@ -255,7 +298,7 @@
out_error:
spin_unlock(&ip->i_flags_lock);
- read_unlock(&pag->pag_ici_lock);
+ rcu_read_unlock();
return error;
}
@@ -308,7 +351,7 @@
BUG();
}
- write_lock(&pag->pag_ici_lock);
+ spin_lock(&pag->pag_ici_lock);
/* insert the new inode */
error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
@@ -323,14 +366,14 @@
ip->i_udquot = ip->i_gdquot = NULL;
xfs_iflags_set(ip, XFS_INEW);
- write_unlock(&pag->pag_ici_lock);
+ spin_unlock(&pag->pag_ici_lock);
radix_tree_preload_end();
*ipp = ip;
return 0;
out_preload_end:
- write_unlock(&pag->pag_ici_lock);
+ spin_unlock(&pag->pag_ici_lock);
radix_tree_preload_end();
if (lock_flags)
xfs_iunlock(ip, lock_flags);
@@ -377,7 +420,7 @@
xfs_agino_t agino;
/* reject inode numbers outside existing AGs */
- if (XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
+ if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
return EINVAL;
/* get the perag structure and ensure that it's inode capable */
@@ -386,15 +429,15 @@
again:
error = 0;
- read_lock(&pag->pag_ici_lock);
+ rcu_read_lock();
ip = radix_tree_lookup(&pag->pag_ici_root, agino);
if (ip) {
- error = xfs_iget_cache_hit(pag, ip, flags, lock_flags);
+ error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
if (error)
goto out_error_or_again;
} else {
- read_unlock(&pag->pag_ici_lock);
+ rcu_read_unlock();
XFS_STATS_INC(xs_ig_missed);
error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,