Date: Sun, 26 Oct 2025 10:53:05 -0600 From: Alan Somers <asomers@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: 6d408ac49073 - main - fusefs: add a regression test for a cluster_read bug Message-ID: <CAOtMX2inFjLj0CcQ=i6D8ert4aEyYNjKLZ0FmsSn1vxFpcqeZw@mail.gmail.com> In-Reply-To: <aPs1Ab7AU0x-Llad@kib.kiev.ua> References: <202510231341.59NDf5as007410@gitrepo.freebsd.org> <aPs1Ab7AU0x-Llad@kib.kiev.ua>
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[-- Attachment #1 --] On Fri, Oct 24, 2025 at 2:13 AM Konstantin Belousov <kostikbel@gmail.com> wrote: > On Thu, Oct 23, 2025 at 01:41:05PM +0000, Alan Somers wrote: > > The branch main has been updated by asomers: > > > > URL: > https://cgit.FreeBSD.org/src/commit/?id=6d408ac490730614b3ed0ebd3caffcd23f303fb4 > > > > commit 6d408ac490730614b3ed0ebd3caffcd23f303fb4 > > Author: Alan Somers <asomers@FreeBSD.org> > > AuthorDate: 2025-10-23 13:40:56 +0000 > > Commit: Alan Somers <asomers@FreeBSD.org> > > CommitDate: 2025-10-23 13:40:56 +0000 > > > > fusefs: add a regression test for a cluster_read bug > > > > VOP_BMAP is purely advisory. If VOP_BMAP returns an error during > > readahead, cluster_read should still succeed, because the actual data > > was still read just fine. > No, VOP_BMAP() is not advisory. But read-ahead beyond the first buffer is. > The BMAP in question is to translate lblk for read-ahead buffer. > > The FUSE_WRITE request _always_ includes the file's nodeid and offset. So unlike, say, UFS, FUSE_BMAP is only used to make decisions about clustering, to compute the amount of readahead. So I suppose I should've said that "FUSE_BMAP is purely advisory". Thanks for the correction. [-- Attachment #2 --] <div dir="ltr"><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Fri, Oct 24, 2025 at 2:13 AM Konstantin Belousov <<a href="mailto:kostikbel@gmail.com">kostikbel@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>On Thu, Oct 23, 2025 at 01:41:05PM +0000, Alan Somers wrote:<br> > The branch main has been updated by asomers:<br> > <br> > URL: <a href="https://cgit.FreeBSD.org/src/commit/?id=6d408ac490730614b3ed0ebd3caffcd23f303fb4" rel="noreferrer" target="_blank">https://cgit.FreeBSD.org/src/commit/?id=6d408ac490730614b3ed0ebd3caffcd23f303fb4</a><br>; > <br> > commit 6d408ac490730614b3ed0ebd3caffcd23f303fb4<br> > Author: Alan Somers <asomers@FreeBSD.org><br> > AuthorDate: 2025-10-23 13:40:56 +0000<br> > Commit: Alan Somers <asomers@FreeBSD.org><br> > CommitDate: 2025-10-23 13:40:56 +0000<br> > <br> > fusefs: add a regression test for a cluster_read bug<br> > <br> > VOP_BMAP is purely advisory. If VOP_BMAP returns an error during<br> > readahead, cluster_read should still succeed, because the actual data<br> > was still read just fine.<br> No, VOP_BMAP() is not advisory. But read-ahead beyond the first buffer is.<br> The BMAP in question is to translate lblk for read-ahead buffer.<br><br></div></blockquote><div> </div><div>The FUSE_WRITE request _always_ includes the file's nodeid and offset. So unlike, say, UFS, FUSE_BMAP is only used to make decisions about clustering, to compute the amount of readahead. So I suppose I should've said that "FUSE_BMAP is purely advisory". Thanks for the correction.</div></div></div>home | help
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