If ext4_da_block_invalidatepages() is called because of a
failure from ext4_map_blocks() in mpage_da_map_and_submit(),
it's supposed to clean up -- including unlock -- all the
pages in the mpd structure. But these values may not match
up, even on a system in which block size == page size:
mpd->b_blocknr != mpd->first_page
mpd->b_size != (mpd->next_page - mpd->first_page)
ext4_da_block_invalidatepages() has been using b_blocknr and
b_size; this patch changes it to use first_page and
next_page.
Tested: I injected a small number (5%) of failures in
ext4_map_blocks() in the case that the flags contain
EXT4_GET_BLOCKS_DELALLOC_RESERVE, and ran fsstress on this
kernel. Without this patch, I got hung tasks every time.
With this patch, I see no hangs in many runs of fsstress.
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
c7f5938adc