queue-4.19/revert-btrfs-honour-fitrim-range-constraints-during-free-space-trim.patch

   1 From dsterba@suse.com  Wed May 29 11:30:42 2019
   2 From: David Sterba <dsterba@suse.com>
   3 Date: Wed, 29 May 2019 19:25:44 +0200
   4 Subject: Revert "btrfs: Honour FITRIM range constraints during free space trim"
   5 To: stable@vger.kernel.org
   6 Cc: David Sterba <dsterba@suse.com>
   7 Message-ID: <20190529172547.30563-2-dsterba@suse.com>
   8
   9 From: David Sterba <dsterba@suse.com>
  10
  11 This reverts commit 8b13bb911f0c0c77d41e5ddc41ad3c127c356b8a.
  12
  13 There is currently no corresponding patch in master due to additional
  14 changes that would be significantly different from plain revert in the
  15 respective stable branch.
  16
  17 The range argument was not handled correctly and could cause trim to
  18 overlap allocated areas or reach beyond the end of the device. The
  19 address space that fitrim normally operates on is in logical
  20 coordinates, while the discards are done on the physical device extents.
  21 This distinction cannot be made with the current ioctl interface and
  22 caused the confusion.
  23
  24 The bug depends on the layout of block groups and does not always
  25 happen. The whole-fs trim (run by default by the fstrim tool) is not
  26 affected.
  27
  28 Signed-off-by: David Sterba <dsterba@suse.com>
  29 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  30 ---
  31  fs/btrfs/extent-tree.c |   25 ++++++-------------------
  32  1 file changed, 6 insertions(+), 19 deletions(-)
  33
  34 --- a/fs/btrfs/extent-tree.c
  35 +++ b/fs/btrfs/extent-tree.c
  36 @@ -10788,9 +10788,9 @@ int btrfs_error_unpin_extent_range(struc
  37   * held back allocations.
  38   */
  39  static int btrfs_trim_free_extents(struct btrfs_device *device,
  40 -                                  struct fstrim_range *range, u64 *trimmed)
  41 +                                  u64 minlen, u64 *trimmed)
  42  {
  43 -       u64 start = range->start, len = 0;
  44 +       u64 start = 0, len = 0;
  45         int ret;
  46
  47         *trimmed = 0;
  48 @@ -10833,8 +10833,8 @@ static int btrfs_trim_free_extents(struc
  49                 if (!trans)
  50                         up_read(&fs_info->commit_root_sem);
  51
  52 -               ret = find_free_dev_extent_start(trans, device, range->minlen,
  53 -                                                start, &start, &len);
  54 +               ret = find_free_dev_extent_start(trans, device, minlen, start,
  55 +                                                &start, &len);
  56                 if (trans) {
  57                         up_read(&fs_info->commit_root_sem);
  58                         btrfs_put_transaction(trans);
  59 @@ -10847,16 +10847,6 @@ static int btrfs_trim_free_extents(struc
  60                         break;
  61                 }
  62
  63 -               /* If we are out of the passed range break */
  64 -               if (start > range->start + range->len - 1) {
  65 -                       mutex_unlock(&fs_info->chunk_mutex);
  66 -                       ret = 0;
  67 -                       break;
  68 -               }
  69 -
  70 -               start = max(range->start, start);
  71 -               len = min(range->len, len);
  72 -
  73                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
  74                 mutex_unlock(&fs_info->chunk_mutex);
  75
  76 @@ -10866,10 +10856,6 @@ static int btrfs_trim_free_extents(struc
  77                 start += len;
  78                 *trimmed += bytes;
  79
  80 -               /* We've trimmed enough */
  81 -               if (*trimmed >= range->len)
  82 -                       break;
  83 -
  84                 if (fatal_signal_pending(current)) {
  85                         ret = -ERESTARTSYS;
  86                         break;
  87 @@ -10953,7 +10939,8 @@ int btrfs_trim_fs(struct btrfs_fs_info *
  88         mutex_lock(&fs_info->fs_devices->device_list_mutex);
  89         devices = &fs_info->fs_devices->devices;
  90         list_for_each_entry(device, devices, dev_list) {
  91 -               ret = btrfs_trim_free_extents(device, range, &group_trimmed);
  92 +               ret = btrfs_trim_free_extents(device, range->minlen,
  93 +                                             &group_trimmed);
  94                 if (ret) {
  95                         dev_failed++;
  96                         dev_ret = ret;