bcachefs: Don't issue writes that are more than 1 MB

the bcachefs io path in io.c can't bounce writes larger than that.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index e713c83530ccc3dbb431ebd1e975172d442a8d88..9644d4624f803bd150ec2a3496a9d14cd736a55f 100644 (file)
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -1177,7 +1177,8 @@ do_io:
                if (w->io &&
                    (w->io->op.res.nr_replicas != nr_replicas_this_write ||
                     bio_full(&w->io->op.wbio.bio, PAGE_SIZE) ||
-                    w->io->op.wbio.bio.bi_iter.bi_size >= (256U << 20) ||
+                    w->io->op.wbio.bio.bi_iter.bi_size + (sectors << 9) >=
+                    (BIO_MAX_VECS * PAGE_SIZE) ||
                     bio_end_sector(&w->io->op.wbio.bio) != sector))
                        bch2_writepage_do_io(w);
 
@@ -1794,12 +1795,22 @@ static long bch2_dio_write_loop(struct dio_write *dio)
                goto loop;
 
        while (1) {
+               size_t extra = dio->iter.count -
+                       min(BIO_MAX_VECS * PAGE_SIZE, dio->iter.count);
+
                if (kthread)
                        kthread_use_mm(dio->mm);
                BUG_ON(current->faults_disabled_mapping);
                current->faults_disabled_mapping = mapping;
 
+               /*
+                * Don't issue more than 2MB at once, the bcachefs io path in
+                * io.c can't bounce more than that:
+                */
+
+               dio->iter.count -= extra;
                ret = bio_iov_iter_get_pages(bio, &dio->iter);
+               dio->iter.count += extra;
 
                current->faults_disabled_mapping = NULL;
                if (kthread)