From: Andreas Gruenbacher agruenba@redhat.com
[ Upstream commit 95ecbd0f162fc06ef4c4045a66f653f47b62a2d3 ]
Commit b2b0a5e97855 switched from generic_writepages() to filemap_fdatawrite_wbc() in gfs2_ail1_start_one() on the path to replacing ->writepage() with ->writepages() and eventually eliminating the former. Function gfs2_ail1_start_one() is called from gfs2_log_flush(), our main function for flushing the filesystem log.
Unfortunately, at least as implemented today, ->writepage() and ->writepages() are entirely different operations for journaled data inodes: while the former creates and submits transactions covering the data to be written, the latter flushes dirty buffers out to disk.
With gfs2_ail1_start_one() now calling ->writepages(), we end up creating filesystem transactions while we are in the course of a log flush, which immediately deadlocks on the sdp->sd_log_flush_lock semaphore.
Work around that by going back to how things used to work before commit b2b0a5e97855 for now; figuring out a superior solution will take time we don't have available right now. However ...
Since the removal of generic_writepages() is imminent, open-code it here. We're already inside a blk_start_plug() ... blk_finish_plug() section here, so skip that part of the original generic_writepages().
This reverts commit b2b0a5e978552e348f85ad9c7568b630a5ede659.
Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Acked-by: Christoph Hellwig hch@lst.de Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/log.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 723639376ae2..61323deb80bc 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -80,6 +80,15 @@ void gfs2_remove_from_ail(struct gfs2_bufdata *bd) brelse(bd->bd_bh); }
+static int __gfs2_writepage(struct page *page, struct writeback_control *wbc, + void *data) +{ + struct address_space *mapping = data; + int ret = mapping->a_ops->writepage(page, wbc); + mapping_set_error(mapping, ret); + return ret; +} + /** * gfs2_ail1_start_one - Start I/O on a transaction * @sdp: The superblock @@ -131,7 +140,7 @@ __acquires(&sdp->sd_ail_lock) if (!mapping) continue; spin_unlock(&sdp->sd_ail_lock); - ret = filemap_fdatawrite_wbc(mapping, wbc); + ret = write_cache_pages(mapping, wbc, __gfs2_writepage, mapping); if (need_resched()) { blk_finish_plug(plug); cond_resched();