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From: Dan Carpenter <dan.carpenter@oracle.com>
To: fdmanana@gmail.com
Cc: linux-btrfs@vger.kernel.org
Subject: re: Btrfs: make fsync work after cloning into a file
Date: Fri, 20 Mar 2015 17:38:40 +0300	[thread overview]
Message-ID: <20150320143840.GC5108@mwanda> (raw)

Hello Filipe Manana,

The patch 7ffbb598a059: "Btrfs: make fsync work after cloning into a
file" from Jun 9, 2014, leads to the following static checker warning:

	fs/btrfs/inode.c:6602 btrfs_get_extent()
	warn: we tested 'create' before and it was 'false'

fs/btrfs/inode.c
  6589  
  6590                  if (new_inline)
                            ^^^^^^^^^^
This implies that "create == 0".

  6591                          goto out;
  6592  
  6593                  size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
  6594                  extent_offset = page_offset(page) + pg_offset - extent_start;
  6595                  copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
  6596                                  size - extent_offset);
  6597                  em->start = extent_start + extent_offset;
  6598                  em->len = ALIGN(copy_size, root->sectorsize);
  6599                  em->orig_block_len = em->len;
  6600                  em->orig_start = em->start;
  6601                  ptr = btrfs_file_extent_inline_start(item) + extent_offset;
  6602                  if (create == 0 && !PageUptodate(page)) {
                            ^^^^^^^^^^^
No need to check here.

  6603                          if (btrfs_file_extent_compression(leaf, item) !=
  6604                              BTRFS_COMPRESS_NONE) {
  6605                                  ret = uncompress_inline(path, inode, page,
  6606                                                          pg_offset,
  6607                                                          extent_offset, item);
  6608                                  if (ret) {
  6609                                          err = ret;
  6610                                          goto out;
  6611                                  }
  6612                          } else {
  6613                                  map = kmap(page);
  6614                                  read_extent_buffer(leaf, map + pg_offset, ptr,
  6615                                                     copy_size);
  6616                                  if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
  6617                                          memset(map + pg_offset + copy_size, 0,
  6618                                                 PAGE_CACHE_SIZE - pg_offset -
  6619                                                 copy_size);
  6620                                  }
  6621                                  kunmap(page);
  6622                          }
  6623                          flush_dcache_page(page);
  6624                  } else if (create && PageUptodate(page)) {
                                   ^^^^^^
Or here.

  6625                          BUG();
  6626                          if (!trans) {

regards,
dan carpenter

             reply	other threads:[~2015-03-20 14:38 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-20 14:38 Dan Carpenter [this message]
2015-03-20 15:10 ` Btrfs: make fsync work after cloning into a file Filipe David Manana

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