queue-4.19/ext4-cleanup-pagecache-before-swap-i_data.patch

   1 From a46c68a318b08f819047843abf349aeee5d10ac2 Mon Sep 17 00:00:00 2001
   2 From: yangerkun <yangerkun@huawei.com>
   3 Date: Mon, 11 Feb 2019 00:05:24 -0500
   4 Subject: ext4: cleanup pagecache before swap i_data
   5
   6 From: yangerkun <yangerkun@huawei.com>
   7
   8 commit a46c68a318b08f819047843abf349aeee5d10ac2 upstream.
   9
  10 While do swap, we should make sure there has no new dirty page since we
  11 should swap i_data between two inode:
  12 1.We should lock i_mmap_sem with write to avoid new pagecache from mmap
  13 read/write;
  14 2.Change filemap_flush to filemap_write_and_wait and move them to the
  15 space protected by inode lock to avoid new pagecache from buffer read/write.
  16
  17 Signed-off-by: yangerkun <yangerkun@huawei.com>
  18 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  19 Cc: stable@kernel.org
  20 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  21
  22 ---
  23  fs/ext4/ioctl.c |   16 ++++++++++++----
  24  1 file changed, 12 insertions(+), 4 deletions(-)
  25
  26 --- a/fs/ext4/ioctl.c
  27 +++ b/fs/ext4/ioctl.c
  28 @@ -121,9 +121,6 @@ static long swap_inode_boot_loader(struc
  29                 return PTR_ERR(inode_bl);
  30         ei_bl = EXT4_I(inode_bl);
  31
  32 -       filemap_flush(inode->i_mapping);
  33 -       filemap_flush(inode_bl->i_mapping);
  34 -
  35         /* Protect orig inodes against a truncate and make sure,
  36          * that only 1 swap_inode_boot_loader is running. */
  37         lock_two_nondirectories(inode, inode_bl);
  38 @@ -141,6 +138,15 @@ static long swap_inode_boot_loader(struc
  39                 goto journal_err_out;
  40         }
  41
  42 +       down_write(&EXT4_I(inode)->i_mmap_sem);
  43 +       err = filemap_write_and_wait(inode->i_mapping);
  44 +       if (err)
  45 +               goto err_out;
  46 +
  47 +       err = filemap_write_and_wait(inode_bl->i_mapping);
  48 +       if (err)
  49 +               goto err_out;
  50 +
  51         /* Wait for all existing dio workers */
  52         inode_dio_wait(inode);
  53         inode_dio_wait(inode_bl);
  54 @@ -151,7 +157,7 @@ static long swap_inode_boot_loader(struc
  55         handle = ext4_journal_start(inode_bl, EXT4_HT_MOVE_EXTENTS, 2);
  56         if (IS_ERR(handle)) {
  57                 err = -EINVAL;
  58 -               goto journal_err_out;
  59 +               goto err_out;
  60         }
  61
  62         /* Protect extent tree against block allocations via delalloc */
  63 @@ -208,6 +214,8 @@ static long swap_inode_boot_loader(struc
  64         ext4_journal_stop(handle);
  65         ext4_double_up_write_data_sem(inode, inode_bl);
  66
  67 +err_out:
  68 +       up_write(&EXT4_I(inode)->i_mmap_sem);
  69  journal_err_out:
  70         unlock_two_nondirectories(inode, inode_bl);
  71         iput(inode_bl);