From: Al Viro Date: Wed, 13 Sep 2023 16:28:15 +0000 (+0200) Subject: direct_write_fallback(): on error revert the ->ki_pos update from buffered write X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8287474aa5ffb41df52552c4ae4748e791d2faf2;p=linux.git direct_write_fallback(): on error revert the ->ki_pos update from buffered write If we fail filemap_write_and_wait_range() on the range the buffered write went into, we only report the "number of bytes which we direct-written", to quote the comment in there. Which is fine, but buffered write has already advanced iocb->ki_pos, so we need to roll that back. Otherwise we end up with e.g. write(2) advancing position by more than the amount it reports having written. Fixes: 182c25e9c157 "filemap: update ki_pos in generic_perform_write" Signed-off-by: Al Viro Message-Id: <20230827214518.GU3390869@ZenIV> Signed-off-by: Christian Brauner --- diff --git a/fs/libfs.c b/fs/libfs.c index a4eb127578862..37f2d34ee090b 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1903,6 +1903,7 @@ ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter, * We don't know how much we wrote, so just return the number of * bytes which were direct-written */ + iocb->ki_pos -= buffered_written; if (direct_written) return direct_written; return err;