On 2018/10/26 下午7:43, Nikolay Borisov wrote:
> lock_delalloc_pages should only return 2 values - 0 in case of success
> and -EAGAIN if the range of pages to be locked should be shrunk due to
> some of gone. Manual inspections confirms that this is
> indeed the case since __process_pages_contig is where lock_delalloc_pages
> gets its return value. The latter always returns 0 or -EAGAIN so the
> invariant holds. No functional changes.
>
> Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
Reviewed-by: Qu Wenruo <wqu@xxxxxxxx>
Thanks,
Qu
> ---
> fs/btrfs/extent_io.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 1a9a521aefe5..94bc53472031 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -1606,6 +1606,7 @@ static noinline_for_stack u64 find_lock_delalloc_range(struct inode *inode,
> /* step two, lock all the pages after the page that has start */
> ret = lock_delalloc_pages(inode, locked_page,
> delalloc_start, delalloc_end);
> + ASSERT(!ret || ret == -EAGAIN);
> if (ret == -EAGAIN) {
> /* some of the pages are gone, lets avoid looping by
> * shortening the size of the delalloc range we're searching
> @@ -1621,7 +1622,6 @@ static noinline_for_stack u64 find_lock_delalloc_range(struct inode *inode,
> goto out_failed;
> }
> }
> - BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
>
> /* step three, lock the state bits for the whole range */
> lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
>
