4.14-stable patches

added patches:
	btrfs-don-t-allocate-anonymous-block-device-for-user-invisible-roots.patch

diff --git a/queue-4.14/btrfs-don-t-allocate-anonymous-block-device-for-user-invisible-roots.patch b/queue-4.14/btrfs-don-t-allocate-anonymous-block-device-for-user-invisible-roots.patch
new file mode 100644 (file)
index 0000000..633033c
--- /dev/null
+++ b/queue-4.14/btrfs-don-t-allocate-anonymous-block-device-for-user-invisible-roots.patch
@@ -0,0 +1,90 @@
+From 851fd730a743e072badaf67caf39883e32439431 Mon Sep 17 00:00:00 2001
+From: Qu Wenruo <wqu@suse.com>
+Date: Tue, 16 Jun 2020 10:17:34 +0800
+Subject: btrfs: don't allocate anonymous block device for user invisible roots
+
+From: Qu Wenruo <wqu@suse.com>
+
+commit 851fd730a743e072badaf67caf39883e32439431 upstream.
+
+[BUG]
+When a lot of subvolumes are created, there is a user report about
+transaction aborted:
+
+  BTRFS: Transaction aborted (error -24)
+  WARNING: CPU: 17 PID: 17041 at fs/btrfs/transaction.c:1576 create_pending_snapshot+0xbc4/0xd10 [btrfs]
+  RIP: 0010:create_pending_snapshot+0xbc4/0xd10 [btrfs]
+  Call Trace:
+   create_pending_snapshots+0x82/0xa0 [btrfs]
+   btrfs_commit_transaction+0x275/0x8c0 [btrfs]
+   btrfs_mksubvol+0x4b9/0x500 [btrfs]
+   btrfs_ioctl_snap_create_transid+0x174/0x180 [btrfs]
+   btrfs_ioctl_snap_create_v2+0x11c/0x180 [btrfs]
+   btrfs_ioctl+0x11a4/0x2da0 [btrfs]
+   do_vfs_ioctl+0xa9/0x640
+   ksys_ioctl+0x67/0x90
+   __x64_sys_ioctl+0x1a/0x20
+   do_syscall_64+0x5a/0x110
+   entry_SYSCALL_64_after_hwframe+0x44/0xa9
+  ---[ end trace 33f2f83f3d5250e9 ]---
+  BTRFS: error (device sda1) in create_pending_snapshot:1576: errno=-24 unknown
+  BTRFS info (device sda1): forced readonly
+  BTRFS warning (device sda1): Skipping commit of aborted transaction.
+  BTRFS: error (device sda1) in cleanup_transaction:1831: errno=-24 unknown
+
+[CAUSE]
+The error is EMFILE (Too many files open) and comes from the anonymous
+block device allocation. The ids are in a shared pool of size 1<<20.
+
+The ids are assigned to live subvolumes, ie. the root structure exists
+in memory (eg. after creation or after the root appears in some path).
+The pool could be exhausted if the numbers are not reclaimed fast
+enough, after subvolume deletion or if other system component uses the
+anon block devices.
+
+[WORKAROUND]
+Since it's not possible to completely solve the problem, we can only
+minimize the time the id is allocated to a subvolume root.
+
+Firstly, we can reduce the use of anon_dev by trees that are not
+subvolume roots, like data reloc tree.
+
+This patch will do extra check on root objectid, to skip roots that
+don't need anon_dev.  Currently it's only data reloc tree and orphan
+roots.
+
+Reported-by: Greed Rong <greedrong@gmail.com>
+Link: https://lore.kernel.org/linux-btrfs/CA+UqX+NTrZ6boGnWHhSeZmEY5J76CTqmYjO2S+=tHJX7nb9DPw@mail.gmail.com/
+CC: stable@vger.kernel.org # 4.4+
+Reviewed-by: Josef Bacik <josef@toxicpanda.com>
+Signed-off-by: Qu Wenruo <wqu@suse.com>
+Reviewed-by: David Sterba <dsterba@suse.com>
+Signed-off-by: David Sterba <dsterba@suse.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/btrfs/disk-io.c |   13 ++++++++++---
+ 1 file changed, 10 insertions(+), 3 deletions(-)
+
+--- a/fs/btrfs/disk-io.c
++++ b/fs/btrfs/disk-io.c
+@@ -1509,9 +1509,16 @@ int btrfs_init_fs_root(struct btrfs_root
+       spin_lock_init(&root->ino_cache_lock);
+       init_waitqueue_head(&root->ino_cache_wait);
+ 
+-      ret = get_anon_bdev(&root->anon_dev);
+-      if (ret)
+-              goto fail;
++      /*
++       * Don't assign anonymous block device to roots that are not exposed to
++       * userspace, the id pool is limited to 1M
++       */
++      if (is_fstree(root->root_key.objectid) &&
++          btrfs_root_refs(&root->root_item) > 0) {
++              ret = get_anon_bdev(&root->anon_dev);
++              if (ret)
++                      goto fail;
++      }
+ 
+       mutex_lock(&root->objectid_mutex);
+       ret = btrfs_find_highest_objectid(root,

diff --git a/queue-4.14/series b/queue-4.14/series
index 3241d32f56ffe3ac2b4470e4463e9db56298eb1a..8ce02d00a8a7f424851bbf90f14c78828a6268c7 100644 (file)
--- a/queue-4.14/series
+++ b/queue-4.14/series
@@ -166,3 +166,4 @@ xen-balloon-make-the-balloon-wait-interruptible.patch
 net-initialize-fastreuse-on-inet_inherit_port.patch
 smb3-warn-on-confusing-error-scenario-with-sec-krb5.patch
 pci-hotplug-acpi-fix-context-refcounting-in-acpiphp_grab_context.patch
+btrfs-don-t-allocate-anonymous-block-device-for-user-invisible-roots.patch