CIFS: FS-Cache: Uncache unread pages in cifs_readpages() before freeing them
In cifs_readpages(), we may decide we don't want to read a page after all -
but the page may already have passed through fscache_read_or_alloc_pages() and
thus have marks and reservations set. Thus we have to call
fscache_readpages_cancel() or fscache_uncache_page() on the pages we're
returning to clear the marks.
NFS, AFS and 9P should be unaffected by this as they call read_cache_pages()
which does the cleanup for you.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index eb955b5..7ddddf2 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3254,6 +3254,9 @@
/*
* Reads as many pages as possible from fscache. Returns -ENOBUFS
* immediately if the cookie is negative
+ *
+ * After this point, every page in the list might have PG_fscache set,
+ * so we will need to clean that up off of every page we don't use.
*/
rc = cifs_readpages_from_fscache(mapping->host, mapping, page_list,
&num_pages);
@@ -3376,6 +3379,11 @@
kref_put(&rdata->refcount, cifs_readdata_release);
}
+ /* Any pages that have been shown to fscache but didn't get added to
+ * the pagecache must be uncached before they get returned to the
+ * allocator.
+ */
+ cifs_fscache_readpages_cancel(mapping->host, page_list);
return rc;
}