Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 041c27e..ccfcc66 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -3,12 +3,14 @@
 
 #include <linux/sort.h>
 #include <linux/slab.h>
-
+#include <linux/iversion.h>
 #include "super.h"
 #include "mds_client.h"
-
 #include <linux/ceph/decode.h>
 
+/* unused map expires after 5 minutes */
+#define CEPH_SNAPID_MAP_TIMEOUT	(5 * 60 * HZ)
+
 /*
  * Snapshots in ceph are driven in large part by cooperation from the
  * client.  In contrast to local file systems or file servers that
@@ -124,6 +126,8 @@
 	INIT_LIST_HEAD(&realm->inodes_with_caps);
 	spin_lock_init(&realm->inodes_with_caps_lock);
 	__insert_snap_realm(&mdsc->snap_realms, realm);
+	mdsc->num_snap_realms++;
+
 	dout("create_snap_realm %llx %p\n", realm->ino, realm);
 	return realm;
 }
@@ -175,6 +179,7 @@
 	dout("__destroy_snap_realm %p %llx\n", realm, realm->ino);
 
 	rb_erase(&realm->node, &mdsc->snap_realms);
+	mdsc->num_snap_realms--;
 
 	if (realm->parent) {
 		list_del_init(&realm->child_item);
@@ -460,6 +465,7 @@
 	struct inode *inode = &ci->vfs_inode;
 	struct ceph_cap_snap *capsnap;
 	struct ceph_snap_context *old_snapc, *new_snapc;
+	struct ceph_buffer *old_blob = NULL;
 	int used, dirty;
 
 	capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS);
@@ -536,7 +542,7 @@
 	capsnap->gid = inode->i_gid;
 
 	if (dirty & CEPH_CAP_XATTR_EXCL) {
-		__ceph_build_xattrs_blob(ci);
+		old_blob = __ceph_build_xattrs_blob(ci);
 		capsnap->xattr_blob =
 			ceph_buffer_get(ci->i_xattrs.blob);
 		capsnap->xattr_version = ci->i_xattrs.version;
@@ -568,12 +574,18 @@
 	old_snapc = NULL;
 
 update_snapc:
-	if (ci->i_head_snapc) {
+       if (ci->i_wrbuffer_ref_head == 0 &&
+           ci->i_wr_ref == 0 &&
+           ci->i_dirty_caps == 0 &&
+           ci->i_flushing_caps == 0) {
+               ci->i_head_snapc = NULL;
+       } else {
 		ci->i_head_snapc = ceph_get_snap_context(new_snapc);
 		dout(" new snapc is %p\n", new_snapc);
 	}
 	spin_unlock(&ci->i_ceph_lock);
 
+	ceph_buffer_put(old_blob);
 	kfree(capsnap);
 	ceph_put_snap_context(old_snapc);
 }
@@ -597,6 +609,8 @@
 	capsnap->mtime = inode->i_mtime;
 	capsnap->atime = inode->i_atime;
 	capsnap->ctime = inode->i_ctime;
+	capsnap->btime = ci->i_btime;
+	capsnap->change_attr = inode_peek_iversion_raw(inode);
 	capsnap->time_warp_seq = ci->i_time_warp_seq;
 	capsnap->truncate_size = ci->i_truncate_size;
 	capsnap->truncate_seq = ci->i_truncate_seq;
@@ -616,7 +630,8 @@
 	     capsnap->size);
 
 	spin_lock(&mdsc->snap_flush_lock);
-	list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);
+	if (list_empty(&ci->i_snap_flush_item))
+		list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);
 	spin_unlock(&mdsc->snap_flush_lock);
 	return 1;  /* caller may want to ceph_flush_snaps */
 }
@@ -638,13 +653,15 @@
 		if (!inode)
 			continue;
 		spin_unlock(&realm->inodes_with_caps_lock);
-		iput(lastinode);
+		/* avoid calling iput_final() while holding
+		 * mdsc->snap_rwsem or in mds dispatch threads */
+		ceph_async_iput(lastinode);
 		lastinode = inode;
 		ceph_queue_cap_snap(ci);
 		spin_lock(&realm->inodes_with_caps_lock);
 	}
 	spin_unlock(&realm->inodes_with_caps_lock);
-	iput(lastinode);
+	ceph_async_iput(lastinode);
 
 	dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
 }
@@ -796,7 +813,9 @@
 		ihold(inode);
 		spin_unlock(&mdsc->snap_flush_lock);
 		ceph_flush_snaps(ci, &session);
-		iput(inode);
+		/* avoid calling iput_final() while holding
+		 * session->s_mutex or in mds dispatch threads */
+		ceph_async_iput(inode);
 		spin_lock(&mdsc->snap_flush_lock);
 	}
 	spin_unlock(&mdsc->snap_flush_lock);
@@ -940,12 +959,14 @@
 			ceph_get_snap_realm(mdsc, realm);
 			ceph_put_snap_realm(mdsc, oldrealm);
 
-			iput(inode);
+			/* avoid calling iput_final() while holding
+			 * mdsc->snap_rwsem or mds in dispatch threads */
+			ceph_async_iput(inode);
 			continue;
 
 skip_inode:
 			spin_unlock(&ci->i_ceph_lock);
-			iput(inode);
+			ceph_async_iput(inode);
 		}
 
 		/* we may have taken some of the old realm's children. */
@@ -985,3 +1006,154 @@
 		up_write(&mdsc->snap_rwsem);
 	return;
 }
+
+struct ceph_snapid_map* ceph_get_snapid_map(struct ceph_mds_client *mdsc,
+					    u64 snap)
+{
+	struct ceph_snapid_map *sm, *exist;
+	struct rb_node **p, *parent;
+	int ret;
+
+	exist = NULL;
+	spin_lock(&mdsc->snapid_map_lock);
+	p = &mdsc->snapid_map_tree.rb_node;
+	while (*p) {
+		exist = rb_entry(*p, struct ceph_snapid_map, node);
+		if (snap > exist->snap) {
+			p = &(*p)->rb_left;
+		} else if (snap < exist->snap) {
+			p = &(*p)->rb_right;
+		} else {
+			if (atomic_inc_return(&exist->ref) == 1)
+				list_del_init(&exist->lru);
+			break;
+		}
+		exist = NULL;
+	}
+	spin_unlock(&mdsc->snapid_map_lock);
+	if (exist) {
+		dout("found snapid map %llx -> %x\n", exist->snap, exist->dev);
+		return exist;
+	}
+
+	sm = kmalloc(sizeof(*sm), GFP_NOFS);
+	if (!sm)
+		return NULL;
+
+	ret = get_anon_bdev(&sm->dev);
+	if (ret < 0) {
+		kfree(sm);
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&sm->lru);
+	atomic_set(&sm->ref, 1);
+	sm->snap = snap;
+
+	exist = NULL;
+	parent = NULL;
+	p = &mdsc->snapid_map_tree.rb_node;
+	spin_lock(&mdsc->snapid_map_lock);
+	while (*p) {
+		parent = *p;
+		exist = rb_entry(*p, struct ceph_snapid_map, node);
+		if (snap > exist->snap)
+			p = &(*p)->rb_left;
+		else if (snap < exist->snap)
+			p = &(*p)->rb_right;
+		else
+			break;
+		exist = NULL;
+	}
+	if (exist) {
+		if (atomic_inc_return(&exist->ref) == 1)
+			list_del_init(&exist->lru);
+	} else {
+		rb_link_node(&sm->node, parent, p);
+		rb_insert_color(&sm->node, &mdsc->snapid_map_tree);
+	}
+	spin_unlock(&mdsc->snapid_map_lock);
+	if (exist) {
+		free_anon_bdev(sm->dev);
+		kfree(sm);
+		dout("found snapid map %llx -> %x\n", exist->snap, exist->dev);
+		return exist;
+	}
+
+	dout("create snapid map %llx -> %x\n", sm->snap, sm->dev);
+	return sm;
+}
+
+void ceph_put_snapid_map(struct ceph_mds_client* mdsc,
+			 struct ceph_snapid_map *sm)
+{
+	if (!sm)
+		return;
+	if (atomic_dec_and_lock(&sm->ref, &mdsc->snapid_map_lock)) {
+		if (!RB_EMPTY_NODE(&sm->node)) {
+			sm->last_used = jiffies;
+			list_add_tail(&sm->lru, &mdsc->snapid_map_lru);
+			spin_unlock(&mdsc->snapid_map_lock);
+		} else {
+			/* already cleaned up by
+			 * ceph_cleanup_snapid_map() */
+			spin_unlock(&mdsc->snapid_map_lock);
+			kfree(sm);
+		}
+	}
+}
+
+void ceph_trim_snapid_map(struct ceph_mds_client *mdsc)
+{
+	struct ceph_snapid_map *sm;
+	unsigned long now;
+	LIST_HEAD(to_free);
+
+	spin_lock(&mdsc->snapid_map_lock);
+	now = jiffies;
+
+	while (!list_empty(&mdsc->snapid_map_lru)) {
+		sm = list_first_entry(&mdsc->snapid_map_lru,
+				      struct ceph_snapid_map, lru);
+		if (time_after(sm->last_used + CEPH_SNAPID_MAP_TIMEOUT, now))
+			break;
+
+		rb_erase(&sm->node, &mdsc->snapid_map_tree);
+		list_move(&sm->lru, &to_free);
+	}
+	spin_unlock(&mdsc->snapid_map_lock);
+
+	while (!list_empty(&to_free)) {
+		sm = list_first_entry(&to_free, struct ceph_snapid_map, lru);
+		list_del(&sm->lru);
+		dout("trim snapid map %llx -> %x\n", sm->snap, sm->dev);
+		free_anon_bdev(sm->dev);
+		kfree(sm);
+	}
+}
+
+void ceph_cleanup_snapid_map(struct ceph_mds_client *mdsc)
+{
+	struct ceph_snapid_map *sm;
+	struct rb_node *p;
+	LIST_HEAD(to_free);
+
+	spin_lock(&mdsc->snapid_map_lock);
+	while ((p = rb_first(&mdsc->snapid_map_tree))) {
+		sm = rb_entry(p, struct ceph_snapid_map, node);
+		rb_erase(p, &mdsc->snapid_map_tree);
+		RB_CLEAR_NODE(p);
+		list_move(&sm->lru, &to_free);
+	}
+	spin_unlock(&mdsc->snapid_map_lock);
+
+	while (!list_empty(&to_free)) {
+		sm = list_first_entry(&to_free, struct ceph_snapid_map, lru);
+		list_del(&sm->lru);
+		free_anon_bdev(sm->dev);
+		if (WARN_ON_ONCE(atomic_read(&sm->ref))) {
+			pr_err("snapid map %llx -> %x still in use\n",
+			       sm->snap, sm->dev);
+		}
+	}
+}