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Message-ID: <158861253957.340223.7465334678444521655.stgit@warthog.procyon.org.uk>
Date: Mon, 04 May 2020 18:15:39 +0100
From: David Howells <dhowells@...hat.com>
To: Trond Myklebust <trondmy@...merspace.com>,
Anna Schumaker <anna.schumaker@...app.com>,
Steve French <sfrench@...ba.org>,
Jeff Layton <jlayton@...hat.com>
Cc: dhowells@...hat.com, Matthew Wilcox <willy@...radead.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
linux-afs@...ts.infradead.org, linux-nfs@...r.kernel.org,
linux-cifs@...r.kernel.org, ceph-devel@...r.kernel.org,
v9fs-developer@...ts.sourceforge.net,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH 54/61] afs: Wait on PG_fscache before modifying/releasing
a page
PG_fscache is going to be used to indicate that a page is being written to
the cache, and that the page should not be modified or released until it's
finished.
Make afs_invalidatepage() and afs_releasepage() wait for it.
Signed-off-by: David Howells <dhowells@...hat.com>
---
fs/afs/file.c | 13 +++++++++++++
fs/afs/write.c | 9 +++++++++
2 files changed, 22 insertions(+)
diff --git a/fs/afs/file.c b/fs/afs/file.c
index ea9f6d45d9ff..b25c5ab1f4e1 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -548,6 +548,11 @@ static void afs_invalidatepage(struct page *page, unsigned int offset,
/* we clean up only if the entire page is being invalidated */
if (offset == 0 && length == PAGE_SIZE) {
+#ifdef CONFIG_AFS_FSCACHE
+ if (PageFsCache(page))
+ wait_on_page_fscache(page);
+#endif
+
if (PagePrivate(page)) {
priv = page_private(page);
trace_afs_page_dirty(vnode, tracepoint_string("inval"),
@@ -575,6 +580,14 @@ static int afs_releasepage(struct page *page, gfp_t gfp_flags)
/* deny if page is being written to the cache and the caller hasn't
* elected to wait */
+#ifdef CONFIG_AFS_FSCACHE
+ if (PageFsCache(page)) {
+ if (!(gfp_flags & __GFP_DIRECT_RECLAIM) || !(gfp_flags & __GFP_FS))
+ return false;
+ wait_on_page_fscache(page);
+ }
+#endif
+
if (PagePrivate(page)) {
priv = page_private(page);
trace_afs_page_dirty(vnode, tracepoint_string("rel"),
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 390fee44446c..3632909fcd91 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -111,6 +111,10 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
SetPageUptodate(page);
}
+#ifdef CONFIG_AFS_FSCACHE
+ wait_on_page_fscache(page);
+#endif
+
/* page won't leak in error case: it eventually gets cleaned off LRU */
*pagep = page;
@@ -786,6 +790,11 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
/* Wait for the page to be written to the cache before we allow it to
* be modified. We then assume the entire page will need writing back.
*/
+#ifdef CONFIG_AFS_FSCACHE
+ if (PageFsCache(vmf->page) &&
+ wait_on_page_bit_killable(vmf->page, PG_fscache) < 0)
+ return VM_FAULT_RETRY;
+#endif
if (PageWriteback(vmf->page) &&
wait_on_page_bit_killable(vmf->page, PG_writeback) < 0)
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