[PATCH 25/19] FS-Cache: NFS: Wait in releasepage() if FS-Cache is busy and __GFP_WAIT is set

[David Howells]

Make NFS wait in its releasepage() op if FS-Cache is busy with a page and
__GFP_WAIT was supplied in the gfp parameter rather than returning false to the
VM.

Signed-Off-By: David Howells <dhowells@xxxxxxxxxx>
---

 fs/nfs/file.c    |    2 +-
 fs/nfs/fscache.h |    9 ++++++---
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 9da03ec..6ac3ac7 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -350,7 +350,7 @@ static int nfs_release_page(struct page 
 	if (nfs_wb_page(page->mapping->host, page) < 0)
 		return 0;
 
-	if (nfs_fscache_release_page(page) < 0)
+	if (nfs_fscache_release_page(page, gfp) < 0)
 		return 0;
 
 	/* PG_private may have been set due to either caching or writing */
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index 92c2dbf..c363421 100644
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -238,10 +238,13 @@ static inline void nfs_fscache_install_v
  * release the caching state associated with a page, if the page isn't busy
  * interacting with the cache
  */
-static inline int nfs_fscache_release_page(struct page *page)
+static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 {
-	if (PageFsMisc(page))
-		return -EBUSY;
+	if (PageFsMisc(page)) {
+		if (!(gfp & __GFP_WAIT))
+			return -EBUSY;
+		wait_on_page_fs_misc(page);
+	}
 
 	if (PageNfsCached(page)) {
 		struct nfs_inode *nfsi = NFS_I(page->mapping->host);
-
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