>From af694f4fc662daf5c62a78391ced5f8e2d4beed2 Mon Sep 17 00:00:00 2001 From: Goldwyn Rodrigues Date: Thu, 13 Feb 2020 13:28:55 -0600 Subject: [PATCH] iomap: return partial I/O count on error in iomap_dio_bio_actor Currently, I/Os that complete with an error indicate this by passing written == 0 to the iomap_end function. However, btrfs needs to know how many bytes were written for its own accounting. Change the convention to pass the number of bytes which were actually written, and change the only user (ext4) to check for a short write instead of a zero length write. In case a filesystem does not define an ->iomap_end(), check for dio->error after the iomap_apply() call to diagnose the error. Signed-off-by: Goldwyn Rodrigues --- fs/ext4/inode.c | 2 +- fs/iomap/direct-io.c | 6 +++++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index fa0ff78dc033..d52c70f851e6 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3475,7 +3475,7 @@ static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length, * the I/O. Any blocks that may have been allocated in preparation for * the direct I/O will be reused during buffered I/O. */ - if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0) + if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written < length) return -ENOTBLK; return 0; diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 41c1e7c20a1f..a0002311cc20 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -264,7 +264,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, size_t n; if (dio->error) { iov_iter_revert(dio->submit.iter, copied); - copied = ret = 0; + ret = 0; goto out; } @@ -499,6 +499,10 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, do { ret = iomap_apply(inode, pos, count, flags, ops, dio, iomap_dio_actor); + + if (ret >= 0 && dio->error) + ret = dio->error; + if (ret <= 0) { /* magic error code to fall back to buffered I/O */ if (ret == -ENOTBLK) { -- 2.25.0