Merge tag 'v3.16-rc4' into drm-intel-next-queued

Due to Dave's vacation drm-next hasn't opened yet for 3.17 so I
couldn't move my drm-intel-next queue forward yet like I usually do.
Just pull in the latest upstream -rc to unblock patch merging - I
don't want to needlessly rebase my current patch pile really and void
all the testing we've done already.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 30 insertions, 10 deletions

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 28cc7bf6575..e62e5947788 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -1613,18 +1613,26 @@ int gfs2_permission(struct inode *inode, int mask)
 {
 	struct gfs2_inode *ip;
 	struct gfs2_holder i_gh;
+	struct gfs2_sbd *sdp = GFS2_SB(inode);
 	int error;
 	int unlock = 0;
+	int frozen_root = 0;
 
 
 	ip = GFS2_I(inode);
 	if (gfs2_glock_is_locked_by_me(ip->i_gl) == NULL) {
-		if (mask & MAY_NOT_BLOCK)
-			return -ECHILD;
-		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
-		if (error)
-			return error;
-		unlock = 1;
+		if (unlikely(gfs2_glock_is_held_excl(sdp->sd_freeze_gl) &&
+			     inode == sdp->sd_root_dir->d_inode &&
+			     atomic_inc_not_zero(&sdp->sd_frozen_root)))
+			frozen_root = 1;
+		else {
+			if (mask & MAY_NOT_BLOCK)
+				return -ECHILD;
+			error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
+			if (error)
+				return error;
+			unlock = 1;
+		}
 	}
 
 	if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode))
@@ -1633,6 +1641,8 @@ int gfs2_permission(struct inode *inode, int mask)
 		error = generic_permission(inode, mask);
 	if (unlock)
 		gfs2_glock_dq_uninit(&i_gh);
+	else if (frozen_root && atomic_dec_and_test(&sdp->sd_frozen_root))
+		wake_up(&sdp->sd_frozen_root_wait);
 
 	return error;
 }
@@ -1805,19 +1815,29 @@ static int gfs2_getattr(struct vfsmount *mnt, struct dentry *dentry,
 	struct inode *inode = dentry->d_inode;
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_holder gh;
+	struct gfs2_sbd *sdp = GFS2_SB(inode);
 	int error;
 	int unlock = 0;
+	int frozen_root = 0;
 
 	if (gfs2_glock_is_locked_by_me(ip->i_gl) == NULL) {
-		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &gh);
-		if (error)
-			return error;
-		unlock = 1;
+		if (unlikely(gfs2_glock_is_held_excl(sdp->sd_freeze_gl) &&
+			     inode == sdp->sd_root_dir->d_inode &&
+			     atomic_inc_not_zero(&sdp->sd_frozen_root)))
+			frozen_root = 1;
+		else {
+			error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &gh);
+			if (error)
+				return error;
+			unlock = 1;
+		}
 	}
 
 	generic_fillattr(inode, stat);
 	if (unlock)
 		gfs2_glock_dq_uninit(&gh);
+	else if (frozen_root && atomic_dec_and_test(&sdp->sd_frozen_root))
+		wake_up(&sdp->sd_frozen_root_wait);
 
 	return 0;
 }