dont-keep-using-page-if-inline-conversion-fails

   1 ext4: don't keep using page if inline conversion fails
   2
   3 From: "Darrick J. Wong" <darrick.wong@oracle.com>
   4
   5 If inline->extent conversion fails (most probably due to ENOSPC) and
   6 we release the temporary page that we allocated to transfer the file
   7 contents, don't keep using the page pointer after releasing the page.
   8 This occasionally leads to complaints about evicting locked pages or
   9 hangs when blocksize > pagesize, because it's possible for the page to
  10 get reallocated elsewhere in the meantime.
  11
  12 Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
  13 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  14 Reviewed-by: Jan Kara <jack@suse.cz>
  15 Cc: Tao Ma <tm@tao.ma>
  16 ---
  17  fs/ext4/inline.c |    4 +++-
  18  1 file changed, 3 insertions(+), 1 deletion(-)
  19
  20
  21 diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
  22 index bea662b..378aadf 100644
  23 --- a/fs/ext4/inline.c
  24 +++ b/fs/ext4/inline.c
  25 @@ -594,6 +594,7 @@ retry:
  26         if (ret) {
  27                 unlock_page(page);
  28                 page_cache_release(page);
  29 +               page = NULL;
  30                 ext4_orphan_add(handle, inode);
  31                 up_write(&EXT4_I(inode)->xattr_sem);
  32                 sem_held = 0;
  33 @@ -613,7 +614,8 @@ retry:
  34         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
  35                 goto retry;
  36
  37 -       block_commit_write(page, from, to);
  38 +       if (page)
  39 +               block_commit_write(page, from, to);
  40  out:
  41         if (page) {
  42                 unlock_page(page);
  43
  44