Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

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;
 }