NFS: Flesh out nfs_invalidate_page()

In the case of a call to truncate_inode_pages(), we should really try to
cancel any pending writes on the page.

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

5 files changed, 60 insertions, 25 deletions

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 63154070145a..106ef0dec04d 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -303,7 +303,11 @@ static int nfs_commit_write(struct file *file, struct page *page, unsigned offse
 
 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 {
-        /* FIXME: we really should cancel any unstarted writes on this page */
+        struct inode *inode = page->mapping->host;
+
+        /* Cancel any unstarted writes on this page */
+        if (offset == 0)
+                nfs_sync_inode_wait(inode, page->index, 1, FLUSH_INVALIDATE);
 }
 
 static int nfs_release_page(struct page *page, gfp_t gfp)
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 106aca388ebc..656481c0daa3 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -325,6 +325,7 @@ out:
 
 /**
  * nfs_scan_list - Scan a list for matching requests
+ * @nfsi: NFS inode
  * @head: One of the NFS inode request lists
  * @dst: Destination list
  * @idx_start: lower bound of page->index to scan
@@ -336,14 +337,15 @@ out:
  * The requests are *not* checked to ensure that they form a contiguous set.
  * You must be holding the inode's req_lock when calling this function
  */
-int
-nfs_scan_list(struct list_head *head, struct list_head *dst,
-              unsigned long idx_start, unsigned int npages)
+int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head,
+                struct list_head *dst, unsigned long idx_start,
+                unsigned int npages)
 {
-        struct list_head        *pos, *tmp;
-        struct nfs_page         *req;
-        unsigned long           idx_end;
-        int                     res;
+        struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES];
+        struct nfs_page *req;
+        unsigned long idx_end;
+        int found, i;
+        int res;
 
         res = 0;
         if (npages == 0)
@@ -351,21 +353,28 @@ nfs_scan_list(struct list_head *head, struct list_head *dst,
         else
                 idx_end = idx_start + npages - 1;
 
-        list_for_each_safe(pos, tmp, head) {
-
-                req = nfs_list_entry(pos);
-
-                if (req->wb_index < idx_start)
-                        continue;
-                if (req->wb_index > idx_end)
+        for (;;) {
+                found = radix_tree_gang_lookup(&nfsi->nfs_page_tree,
+                                (void **)&pgvec[0], idx_start,
+                                NFS_SCAN_MAXENTRIES);
+                if (found <= 0)
                         break;
+                for (i = 0; i < found; i++) {
+                        req = pgvec[i];
+                        if (req->wb_index > idx_end)
+                                goto out;
+                        idx_start = req->wb_index + 1;
+                        if (req->wb_list_head != head)
+                                continue;
+                        if (nfs_set_page_writeback_locked(req)) {
+                                nfs_list_remove_request(req);
+                                nfs_list_add_request(req, dst);
+                                res++;
+                        }
+                }
 
-                if (!nfs_set_page_writeback_locked(req))
-                        continue;
-                nfs_list_remove_request(req);
-                nfs_list_add_request(req, dst);
-                res++;
         }
+out:
         return res;
 }
 
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index a515ec714bb6..e03abbd8302e 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -579,6 +579,17 @@ static int nfs_wait_on_requests(struct inode *inode, unsigned long idx_start, un
         return ret;
 }
 
+static void nfs_cancel_requests(struct list_head *head)
+{
+        struct nfs_page *req;
+        while(!list_empty(head)) {
+                req = nfs_list_entry(head->next);
+                nfs_list_remove_request(req);
+                nfs_inode_remove_request(req);
+                nfs_clear_page_writeback(req);
+        }
+}
+
 /*
  * nfs_scan_dirty - Scan an inode for dirty requests
  * @inode: NFS inode to scan
@@ -623,7 +634,7 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_st
         int res = 0;
 
         if (nfsi->ncommit != 0) {
-                res = nfs_scan_list(&nfsi->commit, dst, idx_start, npages);
+                res = nfs_scan_list(nfsi, &nfsi->commit, dst, idx_start, npages);
                 nfsi->ncommit -= res;
                 if ((nfsi->ncommit == 0) != list_empty(&nfsi->commit))
                         printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n");
@@ -1491,15 +1502,25 @@ int nfs_sync_inode_wait(struct inode *inode, unsigned long idx_start,
                 pages = nfs_scan_dirty(inode, &head, idx_start, npages);
                 if (pages != 0) {
                         spin_unlock(&nfsi->req_lock);
-                        ret = nfs_flush_list(inode, &head, pages, how);
+                        if (how & FLUSH_INVALIDATE)
+                                nfs_cancel_requests(&head);
+                        else
+                                ret = nfs_flush_list(inode, &head, pages, how);
                         spin_lock(&nfsi->req_lock);
                         continue;
                 }
                 if (nocommit)
                         break;
-                pages = nfs_scan_commit(inode, &head, 0, 0);
+                pages = nfs_scan_commit(inode, &head, idx_start, npages);
                 if (pages == 0)
                         break;
+                if (how & FLUSH_INVALIDATE) {
+                        spin_unlock(&nfsi->req_lock);
+                        nfs_cancel_requests(&head);
+                        spin_lock(&nfsi->req_lock);
+                        continue;
+                }
+                pages += nfs_scan_commit(inode, &head, 0, 0);
                 spin_unlock(&nfsi->req_lock);
                 ret = nfs_commit_list(inode, &head, how);
                 spin_lock(&nfsi->req_lock);
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 1b524b9f982a..fc48135621ed 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -61,6 +61,7 @@
 #define FLUSH_LOWPRI            8       /* low priority background flush */
 #define FLUSH_HIGHPRI           16      /* high priority memory reclaim flush */
 #define FLUSH_NOCOMMIT          32      /* Don't send the NFSv3/v4 COMMIT */
+#define FLUSH_INVALIDATE        64      /* Invalidate the page cache */
 
 #ifdef __KERNEL__
 
diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
index 66e2ed658527..8cadb0a77a7a 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -63,8 +63,8 @@ extern	void nfs_release_request(struct nfs_page *req);
 
 extern  int nfs_scan_lock_dirty(struct nfs_inode *nfsi, struct list_head *dst,
                                 unsigned long idx_start, unsigned int npages);
-extern  int nfs_scan_list(struct list_head *, struct list_head *,
-                          unsigned long, unsigned int);
+extern  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
+                          unsigned long idx_start, unsigned int npages);
 extern  int nfs_coalesce_requests(struct list_head *, struct list_head *,
                                   unsigned int);
 extern  int nfs_wait_on_request(struct nfs_page *);