iomap/gfs2: Unlock and put folio in page_done handler
When an iomap defines a ->page_done() handler in its page_ops, delegate
unlocking the folio and putting the folio reference to that handler.
This allows to fix a race between journaled data writes and folio
writeback in gfs2: before this change, gfs2_iomap_page_done() was called
after unlocking the folio, so writeback could start writing back the
folio's buffers before they could be marked for writing to the journal.
Also, try_to_free_buffers() could free the buffers before
gfs2_iomap_page_done() was done adding the buffers to the current
current transaction. With this change, gfs2_iomap_page_done() adds the
buffers to the current transaction while the folio is still locked, so
the problems described above can no longer occur.
The only current user of ->page_done() is gfs2, so other filesystems are
not affected. To catch out any out-of-tree users, switch from a page to
a folio in ->page_done().
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index e7537fd..4620628 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -968,14 +968,23 @@ static int gfs2_iomap_page_prepare(struct inode *inode, loff_t pos,
}
static void gfs2_iomap_page_done(struct inode *inode, loff_t pos,
- unsigned copied, struct page *page)
+ unsigned copied, struct folio *folio)
{
struct gfs2_trans *tr = current->journal_info;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
- if (page && !gfs2_is_stuffed(ip))
- gfs2_page_add_databufs(ip, page, offset_in_page(pos), copied);
+ if (!folio) {
+ gfs2_trans_end(sdp);
+ return;
+ }
+
+ if (!gfs2_is_stuffed(ip))
+ gfs2_page_add_databufs(ip, &folio->page, offset_in_page(pos),
+ copied);
+
+ folio_unlock(folio);
+ folio_put(folio);
if (tr->tr_num_buf_new)
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
