From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Date: Sat, 21 Jan 2023 17:06:41 -0800 Subject: [Cluster-devel] return an ERR_PTR from __filemap_get_folio v2 In-Reply-To: <20230121065755.1140136-1-hch@lst.de> References: <20230121065755.1140136-1-hch@lst.de> Message-ID: <20230121170641.121f4224a0e8304765bb4738@linux-foundation.org> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Sat, 21 Jan 2023 07:57:48 +0100 Christoph Hellwig wrote: > Hi all, > > __filemap_get_folio and its wrappers can return NULL for three different > conditions, which in some cases requires the caller to reverse engineer > the decision making. This is fixed by returning an ERR_PTR instead of > NULL and thus transporting the reason for the failure. But to make > that work we first need to ensure that no xa_value special case is > returned and thus return the FGP_ENTRY flag. It turns out that flag > is barely used and can usually be deal with in a better way. > > Note that the shmem patches in here are non-trivial and need some > careful review and testing. I'll hide for a while, awaiting that review. Plus... > Changes since v1: > - drop the patches to check for errors in btrfs and gfs2 > - document the new calling conventions for the wrappers around > __filemap_get_folio > - rebased against the iomap changes in latest linux-next This patchset doesn't apply to fs/btrfs/ because linux-next contains this 6+ month-old commit: commit 964688b32d9ada55a7fce2e650d85ef24188f73f Author: Matthew Wilcox (Oracle) AuthorDate: Tue May 17 18:03:27 2022 -0400 Commit: Matthew Wilcox (Oracle) CommitDate: Wed Jun 29 08:51:07 2022 -0400 btrfs: Use a folio in wait_dev_supers() Matthew, what's the story here?