git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From f32e48e925964c4f8ab917850788a87e1cef3bad Mon Sep 17 00:00:00 2001
   2 From: Chandan Rajendra <chandan@linux.vnet.ibm.com>
   3 Date: Thu, 7 Jan 2016 18:56:59 +0530
   4 Subject: Btrfs: Initialize btrfs_root->highest_objectid when loading tree root and subvolume roots
   5
   6 From: Chandan Rajendra <chandan@linux.vnet.ibm.com>
   7
   8 commit f32e48e925964c4f8ab917850788a87e1cef3bad upstream.
   9
  10 The following call trace is seen when btrfs/031 test is executed in a loop,
  11
  12 [  158.661848] ------------[ cut here ]------------
  13 [  158.662634] WARNING: CPU: 2 PID: 890 at /home/chandan/repos/linux/fs/btrfs/ioctl.c:558 create_subvol+0x3d1/0x6ea()
  14 [  158.664102] BTRFS: Transaction aborted (error -2)
  15 [  158.664774] Modules linked in:
  16 [  158.665266] CPU: 2 PID: 890 Comm: btrfs Not tainted 4.4.0-rc6-g511711a #2
  17 [  158.666251] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  18 [  158.667392]  ffffffff81c0a6b0 ffff8806c7c4f8e8 ffffffff81431fc8 ffff8806c7c4f930
  19 [  158.668515]  ffff8806c7c4f920 ffffffff81051aa1 ffff880c85aff000 ffff8800bb44d000
  20 [  158.669647]  ffff8808863b5c98 0000000000000000 00000000fffffffe ffff8806c7c4f980
  21 [  158.670769] Call Trace:
  22 [  158.671153]  [<ffffffff81431fc8>] dump_stack+0x44/0x5c
  23 [  158.671884]  [<ffffffff81051aa1>] warn_slowpath_common+0x81/0xc0
  24 [  158.672769]  [<ffffffff81051b27>] warn_slowpath_fmt+0x47/0x50
  25 [  158.673620]  [<ffffffff813bc98d>] create_subvol+0x3d1/0x6ea
  26 [  158.674440]  [<ffffffff813777c9>] btrfs_mksubvol.isra.30+0x369/0x520
  27 [  158.675376]  [<ffffffff8108a4aa>] ? percpu_down_read+0x1a/0x50
  28 [  158.676235]  [<ffffffff81377a81>] btrfs_ioctl_snap_create_transid+0x101/0x180
  29 [  158.677268]  [<ffffffff81377b52>] btrfs_ioctl_snap_create+0x52/0x70
  30 [  158.678183]  [<ffffffff8137afb4>] btrfs_ioctl+0x474/0x2f90
  31 [  158.678975]  [<ffffffff81144b8e>] ? vma_merge+0xee/0x300
  32 [  158.679751]  [<ffffffff8115be31>] ? alloc_pages_vma+0x91/0x170
  33 [  158.680599]  [<ffffffff81123f62>] ? lru_cache_add_active_or_unevictable+0x22/0x70
  34 [  158.681686]  [<ffffffff813d99cf>] ? selinux_file_ioctl+0xff/0x1d0
  35 [  158.682581]  [<ffffffff8117b791>] do_vfs_ioctl+0x2c1/0x490
  36 [  158.683399]  [<ffffffff813d3cde>] ? security_file_ioctl+0x3e/0x60
  37 [  158.684297]  [<ffffffff8117b9d4>] SyS_ioctl+0x74/0x80
  38 [  158.685051]  [<ffffffff819b2bd7>] entry_SYSCALL_64_fastpath+0x12/0x6a
  39 [  158.685958] ---[ end trace 4b63312de5a2cb76 ]---
  40 [  158.686647] BTRFS: error (device loop0) in create_subvol:558: errno=-2 No such entry
  41 [  158.709508] BTRFS info (device loop0): forced readonly
  42 [  158.737113] BTRFS info (device loop0): disk space caching is enabled
  43 [  158.738096] BTRFS error (device loop0): Remounting read-write after error is not allowed
  44 [  158.851303] BTRFS error (device loop0): cleaner transaction attach returned -30
  45
  46 This occurs because,
  47
  48 Mount filesystem
  49 Create subvol with ID 257
  50 Unmount filesystem
  51 Mount filesystem
  52 Delete subvol with ID 257
  53   btrfs_drop_snapshot()
  54     Add root corresponding to subvol 257 into
  55     btrfs_transaction->dropped_roots list
  56 Create new subvol (i.e. create_subvol())
  57   257 is returned as the next free objectid
  58   btrfs_read_fs_root_no_name()
  59     Finds the btrfs_root instance corresponding to the old subvol with ID 257
  60     in btrfs_fs_info->fs_roots_radix.
  61     Returns error since btrfs_root_item->refs has the value of 0.
  62
  63 To fix the issue the commit initializes tree root's and subvolume root's
  64 highest_objectid when loading the roots from disk.
  65
  66 Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
  67 Signed-off-by: David Sterba <dsterba@suse.com>
  68 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  69
  70 ---
  71  fs/btrfs/disk-io.c   |   27 +++++++++++++++++++++++++++
  72  fs/btrfs/inode-map.c |    9 +--------
  73  fs/btrfs/inode-map.h |    1 +
  74  fs/btrfs/ioctl.c     |    4 ++++
  75  4 files changed, 33 insertions(+), 8 deletions(-)
  76
  77 --- a/fs/btrfs/disk-io.c
  78 +++ b/fs/btrfs/disk-io.c
  79 @@ -1582,8 +1582,23 @@ int btrfs_init_fs_root(struct btrfs_root
  80         ret = get_anon_bdev(&root->anon_dev);
  81         if (ret)
  82                 goto free_writers;
  83 +
  84 +       mutex_lock(&root->objectid_mutex);
  85 +       ret = btrfs_find_highest_objectid(root,
  86 +                                       &root->highest_objectid);
  87 +       if (ret) {
  88 +               mutex_unlock(&root->objectid_mutex);
  89 +               goto free_root_dev;
  90 +       }
  91 +
  92 +       ASSERT(root->highest_objectid <= BTRFS_LAST_FREE_OBJECTID);
  93 +
  94 +       mutex_unlock(&root->objectid_mutex);
  95 +
  96         return 0;
  97
  98 +free_root_dev:
  99 +       free_anon_bdev(root->anon_dev);
 100  free_writers:
 101         btrfs_free_subvolume_writers(root->subv_writers);
 102  fail:
 103 @@ -2900,6 +2915,18 @@ retry_root_backup:
 104         tree_root->commit_root = btrfs_root_node(tree_root);
 105         btrfs_set_root_refs(&tree_root->root_item, 1);
 106
 107 +       mutex_lock(&tree_root->objectid_mutex);
 108 +       ret = btrfs_find_highest_objectid(tree_root,
 109 +                                       &tree_root->highest_objectid);
 110 +       if (ret) {
 111 +               mutex_unlock(&tree_root->objectid_mutex);
 112 +               goto recovery_tree_root;
 113 +       }
 114 +
 115 +       ASSERT(tree_root->highest_objectid <= BTRFS_LAST_FREE_OBJECTID);
 116 +
 117 +       mutex_unlock(&tree_root->objectid_mutex);
 118 +
 119         ret = btrfs_read_roots(fs_info, tree_root);
 120         if (ret)
 121                 goto recovery_tree_root;
 122 --- a/fs/btrfs/inode-map.c
 123 +++ b/fs/btrfs/inode-map.c
 124 @@ -515,7 +515,7 @@ out:
 125         return ret;
 126  }
 127
 128 -static int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
 129 +int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
 130  {
 131         struct btrfs_path *path;
 132         int ret;
 133 @@ -555,13 +555,6 @@ int btrfs_find_free_objectid(struct btrf
 134         int ret;
 135         mutex_lock(&root->objectid_mutex);
 136
 137 -       if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
 138 -               ret = btrfs_find_highest_objectid(root,
 139 -                                                 &root->highest_objectid);
 140 -               if (ret)
 141 -                       goto out;
 142 -       }
 143 -
 144         if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
 145                 ret = -ENOSPC;
 146                 goto out;
 147 --- a/fs/btrfs/inode-map.h
 148 +++ b/fs/btrfs/inode-map.h
 149 @@ -9,5 +9,6 @@ int btrfs_save_ino_cache(struct btrfs_ro
 150                          struct btrfs_trans_handle *trans);
 151
 152  int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid);
 153 +int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid);
 154
 155  #endif
 156 --- a/fs/btrfs/ioctl.c
 157 +++ b/fs/btrfs/ioctl.c
 158 @@ -568,6 +568,10 @@ static noinline int create_subvol(struct
 159                 goto fail;
 160         }
 161
 162 +       mutex_lock(&new_root->objectid_mutex);
 163 +       new_root->highest_objectid = new_dirid;
 164 +       mutex_unlock(&new_root->objectid_mutex);
 165 +
 166         /*
 167          * insert the directory item
 168          */