From 31727e2982aeee014e54006c0236d552c4484a74 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 5 Nov 2024 14:56:16 -0700 Subject: [PATCH] iomap: make buffered writes work with RWF_UNCACHED Add iomap buffered write support for RWF_UNCACHED. If RWF_UNCACHED is set for a write, mark the folios being written with drop_writeback. Then writeback completion will drop the pages. The write_iter handler simply kicks off writeback for the pages, and writeback completion will take care of the rest. See the similar patch for the generic filemap handling for performance results, those were in fact done on XFS using this patch. Signed-off-by: Jens Axboe --- fs/iomap/buffered-io.c | 13 ++++++++++++- include/linux/iomap.h | 3 ++- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index ef0b68bccbb6..a81004b66e56 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -959,6 +959,9 @@ retry: } if (iter->iomap.flags & IOMAP_F_STALE) break; + if (iter->flags & IOMAP_UNCACHED && + !(iter->iomap.flags & IOMAP_F_BUFFER_HEAD)) + folio_set_uncached(folio); offset = offset_in_folio(folio, pos); if (bytes > folio_size(folio) - offset) @@ -1023,8 +1026,9 @@ ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, const struct iomap_ops *ops, void *private) { + struct address_space *mapping = iocb->ki_filp->f_mapping; struct iomap_iter iter = { - .inode = iocb->ki_filp->f_mapping->host, + .inode = mapping->host, .pos = iocb->ki_pos, .len = iov_iter_count(i), .flags = IOMAP_WRITE, @@ -1034,12 +1038,19 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, if (iocb->ki_flags & IOCB_NOWAIT) iter.flags |= IOMAP_NOWAIT; + if (iocb->ki_flags & IOCB_UNCACHED) + iter.flags |= IOMAP_UNCACHED; while ((ret = iomap_iter(&iter, ops)) > 0) iter.processed = iomap_write_iter(&iter, i); if (unlikely(iter.pos == iocb->ki_pos)) return ret; + if (iocb->ki_flags & IOCB_UNCACHED) { + /* kick off uncached writeback, completion will drop it */ + __filemap_fdatawrite_range(mapping, iocb->ki_pos, iter.pos, + WB_SYNC_NONE); + } ret = iter.pos - iocb->ki_pos; iocb->ki_pos = iter.pos; return ret; diff --git a/include/linux/iomap.h b/include/linux/iomap.h index f61407e3b121..89b24fbb1399 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -173,8 +173,9 @@ struct iomap_folio_ops { #define IOMAP_NOWAIT (1 << 5) /* do not block */ #define IOMAP_OVERWRITE_ONLY (1 << 6) /* only pure overwrites allowed */ #define IOMAP_UNSHARE (1 << 7) /* unshare_file_range */ +#define IOMAP_UNCACHED (1 << 8) /* uncached IO */ #ifdef CONFIG_FS_DAX -#define IOMAP_DAX (1 << 8) /* DAX mapping */ +#define IOMAP_DAX (1 << 9) /* DAX mapping */ #else #define IOMAP_DAX 0 #endif /* CONFIG_FS_DAX */ -- 2.25.1