[PATCH v2 7/7] vfs: remove inode_set_ctime_deleg()

[Jeff Layton <jlayton@kernel.org>]

Now that nfsd is vetting the timestamps internally, there is no need for
this function. If ATTR_DELEG is set, then skip the multigrain update and
set what was requested.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/attr.c          | 19 +++-----------
 fs/inode.c         | 73 ------------------------------------------------------
 include/linux/fs.h |  2 --
 3 files changed, 4 insertions(+), 90 deletions(-)

diff --git a/fs/attr.c b/fs/attr.c
index f0dabd2985989d283a931536a5fc53eda366b373..e75f06b760015640bafd596457cd14c746c7e272 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -287,14 +287,7 @@ static void setattr_copy_mgtime(struct inode *inode, const struct iattr *attr)
 	struct timespec64 now;
 
 	if (ia_valid & ATTR_CTIME) {
-		/*
-		 * In the case of an update for a write delegation, we must respect
-		 * the value in ia_ctime and not use the current time.
-		 */
-		if (ia_valid & ATTR_DELEG)
-			now = inode_set_ctime_deleg(inode, attr->ia_ctime);
-		else
-			now = inode_set_ctime_current(inode);
+		now = inode_set_ctime_current(inode);
 	} else {
 		/* If ATTR_CTIME isn't set, then ATTR_MTIME shouldn't be either. */
 		WARN_ON_ONCE(ia_valid & ATTR_MTIME);
@@ -352,19 +345,15 @@ void setattr_copy(struct mnt_idmap *idmap, struct inode *inode,
 		inode->i_mode = mode;
 	}
 
-	if (is_mgtime(inode))
+	if (!(ia_valid & ATTR_DELEG) && is_mgtime(inode))
 		return setattr_copy_mgtime(inode, attr);
 
 	if (ia_valid & ATTR_ATIME)
 		inode_set_atime_to_ts(inode, attr->ia_atime);
 	if (ia_valid & ATTR_MTIME)
 		inode_set_mtime_to_ts(inode, attr->ia_mtime);
-	if (ia_valid & ATTR_CTIME) {
-		if (ia_valid & ATTR_DELEG)
-			inode_set_ctime_deleg(inode, attr->ia_ctime);
-		else
-			inode_set_ctime_to_ts(inode, attr->ia_ctime);
-	}
+	if (ia_valid & ATTR_CTIME)
+		inode_set_ctime_to_ts(inode, attr->ia_ctime);
 }
 EXPORT_SYMBOL(setattr_copy);
 
diff --git a/fs/inode.c b/fs/inode.c
index 99318b157a9a13b3dd8dad0f5f90951f08ef64de..f45054fe48b8a0339e60fd2aa17daaad5a7957e7 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2783,79 +2783,6 @@ struct timespec64 inode_set_ctime_current(struct inode *inode)
 }
 EXPORT_SYMBOL(inode_set_ctime_current);
 
-/**
- * inode_set_ctime_deleg - try to update the ctime on a delegated inode
- * @inode: inode to update
- * @update: timespec64 to set the ctime
- *
- * Attempt to atomically update the ctime on behalf of a delegation holder.
- *
- * The nfs server can call back the holder of a delegation to get updated
- * inode attributes, including the mtime. When updating the mtime, update
- * the ctime to a value at least equal to that.
- *
- * This can race with concurrent updates to the inode, in which
- * case the update is skipped.
- *
- * Note that this works even when multigrain timestamps are not enabled,
- * so it is used in either case.
- */
-struct timespec64 inode_set_ctime_deleg(struct inode *inode, struct timespec64 update)
-{
-	struct timespec64 now, cur_ts;
-	u32 cur, old;
-
-	/* pairs with try_cmpxchg below */
-	cur = smp_load_acquire(&inode->i_ctime_nsec);
-	cur_ts.tv_nsec = cur & ~I_CTIME_QUERIED;
-	cur_ts.tv_sec = inode->i_ctime_sec;
-
-	/* If the update is older than the existing value, skip it. */
-	if (timespec64_compare(&update, &cur_ts) <= 0)
-		return cur_ts;
-
-	ktime_get_coarse_real_ts64_mg(&now);
-
-	/* Clamp the update to "now" if it's in the future */
-	if (timespec64_compare(&update, &now) > 0)
-		update = now;
-
-	update = timestamp_truncate(update, inode);
-
-	/* No need to update if the values are already the same */
-	if (timespec64_equal(&update, &cur_ts))
-		return cur_ts;
-
-	/*
-	 * Try to swap the nsec value into place. If it fails, that means
-	 * it raced with an update due to a write or similar activity. That
-	 * stamp takes precedence, so just skip the update.
-	 */
-retry:
-	old = cur;
-	if (try_cmpxchg(&inode->i_ctime_nsec, &cur, update.tv_nsec)) {
-		inode->i_ctime_sec = update.tv_sec;
-		mgtime_counter_inc(mg_ctime_swaps);
-		return update;
-	}
-
-	/*
-	 * Was the change due to another task marking the old ctime QUERIED?
-	 *
-	 * If so, then retry the swap. This can only happen once since
-	 * the only way to clear I_CTIME_QUERIED is to stamp the inode
-	 * with a new ctime.
-	 */
-	if (!(old & I_CTIME_QUERIED) && (cur == (old | I_CTIME_QUERIED)))
-		goto retry;
-
-	/* Otherwise, it was a new timestamp. */
-	cur_ts.tv_sec = inode->i_ctime_sec;
-	cur_ts.tv_nsec = cur & ~I_CTIME_QUERIED;
-	return cur_ts;
-}
-EXPORT_SYMBOL(inode_set_ctime_deleg);
-
 /**
  * in_group_or_capable - check whether caller is CAP_FSETID privileged
  * @idmap:	idmap of the mount @inode was found from
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f18f45e88545c39716b917b1378fb7248367b41d..08f2d813dd40b5dd4fe07d9636e94252915d6235 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1657,8 +1657,6 @@ static inline bool fsuidgid_has_mapping(struct super_block *sb,
 
 struct timespec64 current_time(struct inode *inode);
 struct timespec64 inode_set_ctime_current(struct inode *inode);
-struct timespec64 inode_set_ctime_deleg(struct inode *inode,
-					struct timespec64 update);
 
 static inline time64_t inode_get_atime_sec(const struct inode *inode)
 {

-- 
2.50.1