From: Matthew Wilcox <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org, v9fs-developer@lists.sourceforge.net,
linux-kernel@vger.kernel.org, linux-afs@lists.infradead.org,
ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org,
ecryptfs@vger.kernel.org, linux-um@lists.infradead.org,
linux-mtd@lists.infradead.org,
Richard Weinberger <richard@nod.at>
Subject: Re: [PATCH 01/13] mm: Add AOP_UPDATED_PAGE return value
Date: Thu, 17 Sep 2020 23:03:07 +0100 [thread overview]
Message-ID: <20200917220307.GX5449@casper.infradead.org> (raw)
In-Reply-To: <20200917151050.5363-2-willy@infradead.org>
On Thu, Sep 17, 2020 at 04:10:38PM +0100, Matthew Wilcox (Oracle) wrote:
> +++ b/mm/filemap.c
> @@ -2254,8 +2254,10 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
> * PG_error will be set again if readpage fails.
> */
> ClearPageError(page);
> - /* Start the actual read. The read will unlock the page. */
> + /* Start the actual read. The read may unlock the page. */
> error = mapping->a_ops->readpage(filp, page);
> + if (error == AOP_UPDATED_PAGE)
> + goto page_ok;
>
> if (unlikely(error)) {
> if (error == AOP_TRUNCATED_PAGE) {
If anybody wants to actually test this, this hunk is wrong.
+++ b/mm/filemap.c
@@ -2256,8 +2256,11 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
ClearPageError(page);
/* Start the actual read. The read may unlock the page. */
error = mapping->a_ops->readpage(filp, page);
- if (error == AOP_UPDATED_PAGE)
+ if (error == AOP_UPDATED_PAGE) {
+ unlock_page(page);
+ error = 0;
goto page_ok;
+ }
if (unlikely(error)) {
if (error == AOP_TRUNCATED_PAGE) {
> @@ -2619,7 +2621,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
> */
> if (unlikely(!PageUptodate(page)))
> goto page_not_uptodate;
> -
> +page_ok:
> /*
> * We've made it this far and we had to drop our mmap_lock, now is the
> * time to return to the upper layer and have it re-find the vma and
> @@ -2654,6 +2656,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
> ClearPageError(page);
> fpin = maybe_unlock_mmap_for_io(vmf, fpin);
> error = mapping->a_ops->readpage(file, page);
> + if (error == AOP_UPDATED_PAGE)
> + goto page_ok;
> if (!error) {
> wait_on_page_locked(page);
> if (!PageUptodate(page))
> @@ -2867,6 +2871,10 @@ static struct page *do_read_cache_page(struct address_space *mapping,
> err = filler(data, page);
> else
> err = mapping->a_ops->readpage(data, page);
> + if (err == AOP_UPDATED_PAGE) {
> + unlock_page(page);
> + goto out;
> + }
>
> if (err < 0) {
> put_page(page);
> --
> 2.28.0
>
next prev parent reply other threads:[~2020-09-17 22:03 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 15:10 [PATCH 00/13] Allow readpage to return a locked page Matthew Wilcox (Oracle)
2020-09-17 15:10 ` [PATCH 01/13] mm: Add AOP_UPDATED_PAGE return value Matthew Wilcox (Oracle)
2020-09-17 22:03 ` Matthew Wilcox [this message]
2020-09-17 15:10 ` [PATCH 02/13] 9p: Tell the VFS that readpage was synchronous Matthew Wilcox (Oracle)
2020-09-18 5:59 ` [V9fs-developer] " Dominique Martinet
2020-09-18 11:19 ` Matthew Wilcox
2020-09-18 12:30 ` Dominique Martinet
2020-09-17 15:10 ` [PATCH 03/13] afs: " Matthew Wilcox (Oracle)
2020-09-17 15:10 ` [PATCH 04/13] ceph: " Matthew Wilcox (Oracle)
2020-09-17 16:49 ` Jeff Layton
2020-09-17 15:10 ` [PATCH 05/13] cifs: " Matthew Wilcox (Oracle)
2020-09-17 15:10 ` [PATCH 06/13] cramfs: " Matthew Wilcox (Oracle)
2020-09-17 15:10 ` [PATCH 07/13] ecryptfs: " Matthew Wilcox (Oracle)
2020-09-17 15:10 ` [PATCH 08/13] fuse: " Matthew Wilcox (Oracle)
2020-09-17 15:10 ` [PATCH 09/13] hostfs: " Matthew Wilcox (Oracle)
2020-09-17 15:10 ` [PATCH 10/13] jffs2: " Matthew Wilcox (Oracle)
2020-09-17 15:10 ` [PATCH 11/13] ubifs: " Matthew Wilcox (Oracle)
2020-09-17 20:46 ` Richard Weinberger
2020-09-17 15:10 ` [PATCH 12/13] udf: " Matthew Wilcox (Oracle)
2020-09-24 9:00 ` Jan Kara
2020-09-17 15:10 ` [PATCH 13/13] vboxsf: " Matthew Wilcox (Oracle)
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