[PATCH v3 1/7] iomap: Increase iomap_dio_zero() size limit
From: John Garry <john.g.garry@oracle.com>
Date: 2025-01-02 14:04:52
Also in:
linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), filesystems [iomap], the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
Currently iomap_dio_zero() is limited to using a single bio to write up to 64K. To support atomic writes larger than the FS block size, it may be required to pre-zero some extents larger than 64K. To increase the limit, fill each bio up in a loop. Signed-off-by: John Garry <john.g.garry@oracle.com> --- fs/iomap/direct-io.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index b521eb15759e..23fdad16e6a8 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c@@ -240,27 +240,35 @@ void iomap_dio_bio_end_io(struct bio *bio) EXPORT_SYMBOL_GPL(iomap_dio_bio_end_io); static int iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio, - loff_t pos, unsigned len) + const loff_t pos, const unsigned len) { struct inode *inode = file_inode(dio->iocb->ki_filp); + unsigned int remaining = len; + unsigned int nr_vecs; struct bio *bio; + int i; if (!len) return 0; - /* - * Max block size supported is 64k - */ - if (WARN_ON_ONCE(len > IOMAP_ZERO_PAGE_SIZE)) + + nr_vecs = DIV_ROUND_UP(len, IOMAP_ZERO_PAGE_SIZE); + if (WARN_ON_ONCE(nr_vecs > BIO_MAX_VECS)) return -EINVAL; - bio = iomap_dio_alloc_bio(iter, dio, 1, REQ_OP_WRITE | REQ_SYNC | REQ_IDLE); + bio = iomap_dio_alloc_bio(iter, dio, nr_vecs, + REQ_OP_WRITE | REQ_SYNC | REQ_IDLE); fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits, GFP_KERNEL); bio->bi_iter.bi_sector = iomap_sector(&iter->iomap, pos); bio->bi_private = dio; bio->bi_end_io = iomap_dio_bio_end_io; - __bio_add_page(bio, zero_page, len, 0); + for (i = 0; i < nr_vecs; i++) { + __bio_add_page(bio, zero_page, + min(remaining, IOMAP_ZERO_PAGE_SIZE), 0); + remaining -= IOMAP_ZERO_PAGE_SIZE; + } + iomap_dio_submit_bio(iter, dio, bio, pos); return 0; }
--
2.31.1