From 80baab88bb93eeaa133b426d24dfc0775a8cf824 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Sun, 15 Jan 2023 08:45:51 -0800 Subject: 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 Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Darrick J. Wong --- fs/gfs2/bmap.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index e7537fd305dd..46206286ad42 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); -- cgit v1.2.1