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authorTrond Myklebust <trond.myklebust@primarydata.com>2017-08-01 19:26:53 +0300
committerTrond Myklebust <trond.myklebust@primarydata.com>2017-08-15 18:54:47 +0300
commitb30d2f04c35d539bf8003b3e014c389abefc249b (patch)
treed9545ae599d39524d44bc4323f6526df01789d59 /fs/nfs
parentbd37d6fce184836bd5e7cd90ce40116a4fadaf2a (diff)
downloadlinux-b30d2f04c35d539bf8003b3e014c389abefc249b.tar.xz
NFS: Refactor nfs_page_find_head_request()
Split out the 2 cases so that we can treat the locking differently. The issue is that the locking in the pageswapcache cache is highly linked to the commit list locking. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/write.c42
1 files changed, 30 insertions, 12 deletions
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index a06167e20b72..8d8fa6d4cfcc 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -170,20 +170,41 @@ nfs_page_private_request(struct page *page)
* returns matching head request with reference held, or NULL if not found.
*/
static struct nfs_page *
-nfs_page_find_head_request_locked(struct nfs_inode *nfsi, struct page *page)
+nfs_page_find_private_request(struct page *page)
{
+ struct inode *inode = page_file_mapping(page)->host;
struct nfs_page *req;
+ if (!PagePrivate(page))
+ return NULL;
+ spin_lock(&inode->i_lock);
req = nfs_page_private_request(page);
- if (!req && unlikely(PageSwapCache(page)))
- req = nfs_page_search_commits_for_head_request_locked(nfsi,
- page);
-
if (req) {
WARN_ON_ONCE(req->wb_head != req);
kref_get(&req->wb_kref);
}
+ spin_unlock(&inode->i_lock);
+ return req;
+}
+static struct nfs_page *
+nfs_page_find_swap_request(struct page *page)
+{
+ struct inode *inode = page_file_mapping(page)->host;
+ struct nfs_inode *nfsi = NFS_I(inode);
+ struct nfs_page *req = NULL;
+ if (!PageSwapCache(page))
+ return NULL;
+ spin_lock(&inode->i_lock);
+ if (PageSwapCache(page)) {
+ req = nfs_page_search_commits_for_head_request_locked(nfsi,
+ page);
+ if (req) {
+ WARN_ON_ONCE(req->wb_head != req);
+ kref_get(&req->wb_kref);
+ }
+ }
+ spin_unlock(&inode->i_lock);
return req;
}
@@ -194,14 +215,11 @@ nfs_page_find_head_request_locked(struct nfs_inode *nfsi, struct page *page)
*/
static struct nfs_page *nfs_page_find_head_request(struct page *page)
{
- struct inode *inode = page_file_mapping(page)->host;
- struct nfs_page *req = NULL;
+ struct nfs_page *req;
- if (PagePrivate(page) || PageSwapCache(page)) {
- spin_lock(&inode->i_lock);
- req = nfs_page_find_head_request_locked(NFS_I(inode), page);
- spin_unlock(&inode->i_lock);
- }
+ req = nfs_page_find_private_request(page);
+ if (!req)
+ req = nfs_page_find_swap_request(page);
return req;
}