Merge tag 'for-5.6-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Two races fixed, memory leak fix, sysfs directory fixup and two new
  log messages:

   - two fixed race conditions: extent map merging and truncate vs
     fiemap

   - create the right sysfs directory with device information and move
     the individual device dirs under it

   - print messages when the tree-log is replayed at mount time or
     cannot be replayed on remount"

* tag 'for-5.6-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: sysfs, move device id directories to UUID/devinfo
  btrfs: sysfs, add UUID/devinfo kobject
  Btrfs: fix race between shrinking truncate and fiemap
  btrfs: log message when rw remount is attempted with unclean tree-log
  btrfs: print message when tree-log replay starts
  Btrfs: fix race between using extent maps and merging them
  btrfs: ref-verify: fix memory leaks

7 files changed, 44 insertions, 1 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7fa9bb79ad08..89422aa8e9d1 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3164,6 +3164,7 @@ int __cold open_ctree(struct super_block *sb,
 	/* do not make disk changes in broken FS or nologreplay is given */
 	if (btrfs_super_log_root(disk_super) != 0 &&
 	    !btrfs_test_opt(fs_info, NOLOGREPLAY)) {
+		btrfs_info(fs_info, "start tree-log replay");
 		ret = btrfs_replay_log(fs_info, fs_devices);
 		if (ret) {
 			err = ret;
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 6f417ff68980..bd6229fb2b6f 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -237,6 +237,17 @@ static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
 	struct extent_map *merge = NULL;
 	struct rb_node *rb;
 
+	/*
+	 * We can't modify an extent map that is in the tree and that is being
+	 * used by another task, as it can cause that other task to see it in
+	 * inconsistent state during the merging. We always have 1 reference for
+	 * the tree and 1 for this task (which is unpinning the extent map or
+	 * clearing the logging flag), so anything > 2 means it's being used by
+	 * other tasks too.
+	 */
+	if (refcount_read(&em->refs) > 2)
+		return;
+
 	if (em->start != 0) {
 		rb = rb_prev(&em->rb_node);
 		if (rb)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5b3ec93ff911..7d26b4bfb2c6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4085,6 +4085,8 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 	u64 bytes_deleted = 0;
 	bool be_nice = false;
 	bool should_throttle = false;
+	const u64 lock_start = ALIGN_DOWN(new_size, fs_info->sectorsize);
+	struct extent_state *cached_state = NULL;
 
 	BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
 
@@ -4101,6 +4103,9 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 		return -ENOMEM;
 	path->reada = READA_BACK;
 
+	lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, (u64)-1,
+			 &cached_state);
+
 	/*
 	 * We want to drop from the next block forward in case this new size is
 	 * not block aligned since we will be keeping the last block of the
@@ -4367,6 +4372,9 @@ out:
 		btrfs_ordered_update_i_size(inode, last_size, NULL);
 	}
 
+	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, (u64)-1,
+			     &cached_state);
+
 	btrfs_free_path(path);
 	return ret;
 }
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
index b57f3618e58e..454a1015d026 100644
--- a/fs/btrfs/ref-verify.c
+++ b/fs/btrfs/ref-verify.c
@@ -744,6 +744,7 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
 		 */
 		be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
 		if (IS_ERR(be)) {
+			kfree(ref);
 			kfree(ra);
 			ret = PTR_ERR(be);
 			goto out;
@@ -757,6 +758,8 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
 			"re-allocated a block that still has references to it!");
 			dump_block_entry(fs_info, be);
 			dump_ref_action(fs_info, ra);
+			kfree(ref);
+			kfree(ra);
 			goto out_unlock;
 		}
 
@@ -819,6 +822,7 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
 "dropping a ref for a existing root that doesn't have a ref on the block");
 				dump_block_entry(fs_info, be);
 				dump_ref_action(fs_info, ra);
+				kfree(ref);
 				kfree(ra);
 				goto out_unlock;
 			}
@@ -834,6 +838,7 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
 "attempting to add another ref for an existing ref on a tree block");
 			dump_block_entry(fs_info, be);
 			dump_ref_action(fs_info, ra);
+			kfree(ref);
 			kfree(ra);
 			goto out_unlock;
 		}
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 0616a5434793..67c63858812a 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1834,6 +1834,8 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 		}
 
 		if (btrfs_super_log_root(fs_info->super_copy) != 0) {
+			btrfs_warn(fs_info,
+		"mount required to replay tree-log, cannot remount read-write");
 			ret = -EINVAL;
 			goto restore;
 		}
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 7436422194da..3c10e78924d0 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -901,6 +901,12 @@ static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
 
 static void __btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs)
 {
+	if (fs_devs->devinfo_kobj) {
+		kobject_del(fs_devs->devinfo_kobj);
+		kobject_put(fs_devs->devinfo_kobj);
+		fs_devs->devinfo_kobj = NULL;
+	}
+
 	if (fs_devs->devices_kobj) {
 		kobject_del(fs_devs->devices_kobj);
 		kobject_put(fs_devs->devices_kobj);
@@ -1289,7 +1295,7 @@ int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices,
 
 		init_completion(&dev->kobj_unregister);
 		error = kobject_init_and_add(&dev->devid_kobj, &devid_ktype,
-					     fs_devices->devices_kobj, "%llu",
+					     fs_devices->devinfo_kobj, "%llu",
 					     dev->devid);
 		if (error) {
 			kobject_put(&dev->devid_kobj);
@@ -1369,6 +1375,15 @@ int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs)
 		return -ENOMEM;
 	}
 
+	fs_devs->devinfo_kobj = kobject_create_and_add("devinfo",
+						       &fs_devs->fsid_kobj);
+	if (!fs_devs->devinfo_kobj) {
+		btrfs_err(fs_devs->fs_info,
+			  "failed to init sysfs devinfo kobject");
+		btrfs_sysfs_remove_fsid(fs_devs);
+		return -ENOMEM;
+	}
+
 	return 0;
 }
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 409f4816fb89..f01552a0785e 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -258,6 +258,7 @@ struct btrfs_fs_devices {
 	/* sysfs kobjects */
 	struct kobject fsid_kobj;
 	struct kobject *devices_kobj;
+	struct kobject *devinfo_kobj;
 	struct completion kobj_unregister;
 };