NFS: Clean up the write request locking.

Ensure that we set/clear NFS_PAGE_TAG_LOCKED when the nfs_page is hashed.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 16 insertions, 26 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 345bb9b4765b..3b3dbb94393d 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -111,13 +111,14 @@ void nfs_unlock_request(struct nfs_page *req)
  * nfs_set_page_tag_locked - Tag a request as locked
  * @req:
  */
-static int nfs_set_page_tag_locked(struct nfs_page *req)
+int nfs_set_page_tag_locked(struct nfs_page *req)
 {
         struct nfs_inode *nfsi = NFS_I(req->wb_context->path.dentry->d_inode);
 
-        if (!nfs_lock_request(req))
+        if (!nfs_lock_request_dontget(req))
                 return 0;
-        radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED);
+        if (req->wb_page != NULL)
+                radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED);
         return 1;
 }
 
@@ -132,9 +133,10 @@ void nfs_clear_page_tag_locked(struct nfs_page *req)
         if (req->wb_page != NULL) {
                 spin_lock(&inode->i_lock);
                 radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED);
+                nfs_unlock_request(req);
                 spin_unlock(&inode->i_lock);
-        }
-        nfs_unlock_request(req);
+        } else
+                nfs_unlock_request(req);
 }
 
 /**
@@ -421,6 +423,7 @@ int nfs_scan_list(struct nfs_inode *nfsi,
                                 goto out;
                         idx_start = req->wb_index + 1;
                         if (nfs_set_page_tag_locked(req)) {
+                                kref_get(&req->wb_kref);
                                 nfs_list_remove_request(req);
                                 radix_tree_tag_clear(&nfsi->nfs_page_tree,
                                                 req->wb_index, tag);
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 51cc1bd6a116..092e79c6d962 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -196,7 +196,7 @@ static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
         }
         /* Update file length */
         nfs_grow_file(page, offset, count);
-        nfs_unlock_request(req);
+        nfs_clear_page_tag_locked(req);
         return 0;
 }
 
@@ -252,7 +252,6 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
                                 struct page *page)
 {
         struct inode *inode = page->mapping->host;
-        struct nfs_inode *nfsi = NFS_I(inode);
         struct nfs_page *req;
         int ret;
 
@@ -263,10 +262,10 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
                         spin_unlock(&inode->i_lock);
                         return 0;
                 }
-                if (nfs_lock_request_dontget(req))
+                if (nfs_set_page_tag_locked(req))
                         break;
                 /* Note: If we hold the page lock, as is the case in nfs_writepage,
-                 *       then the call to nfs_lock_request_dontget() will always
+                 *       then the call to nfs_set_page_tag_locked() will always
                  *       succeed provided that someone hasn't already marked the
                  *       request as dirty (in which case we don't care).
                  */
@@ -280,7 +279,7 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
         if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
                 /* This request is marked for commit */
                 spin_unlock(&inode->i_lock);
-                nfs_unlock_request(req);
+                nfs_clear_page_tag_locked(req);
                 nfs_pageio_complete(pgio);
                 return 0;
         }
@@ -288,8 +287,6 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
                 spin_unlock(&inode->i_lock);
                 BUG();
         }
-        radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
-                        NFS_PAGE_TAG_LOCKED);
         spin_unlock(&inode->i_lock);
         nfs_pageio_add_request(pgio, req);
         return 0;
@@ -381,6 +378,7 @@ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
         set_page_private(req->wb_page, (unsigned long)req);
         nfsi->npages++;
         kref_get(&req->wb_kref);
+        radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED);
         return 0;
 }
 
@@ -596,7 +594,7 @@ static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
                 spin_lock(&inode->i_lock);
                 req = nfs_page_find_request_locked(page);
                 if (req) {
-                        if (!nfs_lock_request_dontget(req)) {
+                        if (!nfs_set_page_tag_locked(req)) {
                                 int error;
 
                                 spin_unlock(&inode->i_lock);
@@ -646,7 +644,7 @@ static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
             || req->wb_page != page
             || !nfs_dirty_request(req)
             || offset > rqend || end < req->wb_offset) {
-                nfs_unlock_request(req);
+                nfs_clear_page_tag_locked(req);
                 return ERR_PTR(-EBUSY);
         }
 
diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
index 30dbcc185e69..a1676e19e491 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -83,6 +83,7 @@ extern	void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 extern  int nfs_wait_on_request(struct nfs_page *);
 extern  void nfs_unlock_request(struct nfs_page *req);
+extern  int nfs_set_page_tag_locked(struct nfs_page *req);
 extern  void nfs_clear_page_tag_locked(struct nfs_page *req);
 
 
@@ -95,18 +96,6 @@ nfs_lock_request_dontget(struct nfs_page *req)
         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 }
 
-/*
- * Lock the page of an asynchronous request and take a reference
- */
-static inline int
-nfs_lock_request(struct nfs_page *req)
-{
-        if (test_and_set_bit(PG_BUSY, &req->wb_flags))
-                return 0;
-        kref_get(&req->wb_kref);
-        return 1;
-}
-
 /**
  * nfs_list_add_request - Insert a request into a list
  * @req: request