Commit c7f5938a authored by Curt Wohlgemuth's avatar Curt Wohlgemuth Committed by Theodore Ts'o
Browse files

ext4: fix ext4_da_block_invalidatepages() to handle page range properly 



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: default avatarCurt Wohlgemuth <curtw@google.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent e0fd9b90

fs/ext4/inode.c

+4 −7
Original line number Diff line number Diff line
@@ -2165,8 +2165,7 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd, 
	return ret;

}



static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,

					sector_t logical, long blk_cnt)

static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd)

{

	int nr_pages, i;

	pgoff_t index, end;
@@ -2174,9 +2173,8 @@ static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd, 
	struct inode *inode = mpd->inode;

	struct address_space *mapping = inode->i_mapping;



	index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);

	end   = (logical + blk_cnt - 1) >>

				(PAGE_CACHE_SHIFT - inode->i_blkbits);

	index = mpd->first_page;

	end   = mpd->next_page - 1;

	while (index <= end) {

		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);

		if (nr_pages == 0)
@@ -2312,8 +2310,7 @@ static void mpage_da_map_and_submit(struct mpage_da_data *mpd) 
				ext4_print_free_blocks(mpd->inode);

		}

		/* invalidate all the pages */

		ext4_da_block_invalidatepages(mpd, next,

				mpd->b_size >> mpd->inode->i_blkbits);

		ext4_da_block_invalidatepages(mpd);



		/* Mark this page range as having been completed */

		mpd->io_done = 1;

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