Merge branch 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6

* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
  NFS: Ensure that writepage respects the nonblock flag
  NFS: kswapd must not block in nfs_release_page
  nfs: include space for the NUL in root path

3 files changed, 31 insertions, 11 deletions

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 36a5e74f51b4..f036153d9f50 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -27,6 +27,7 @@
 #include <linux/pagemap.h>
 #include <linux/aio.h>
 #include <linux/gfp.h>
+#include <linux/swap.h>
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
@@ -493,11 +494,19 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset)
  */
 static int nfs_release_page(struct page *page, gfp_t gfp)
 {
+        struct address_space *mapping = page->mapping;
+
         dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
 
         /* Only do I/O if gfp is a superset of GFP_KERNEL */
-        if ((gfp & GFP_KERNEL) == GFP_KERNEL)
-                nfs_wb_page(page->mapping->host, page);
+        if (mapping && (gfp & GFP_KERNEL) == GFP_KERNEL) {
+                int how = FLUSH_SYNC;
+
+                /* Don't let kswapd deadlock waiting for OOM RPC calls */
+                if (current_is_kswapd())
+                        how = 0;
+                nfs_commit_inode(mapping->host, how);
+        }
         /* If PagePrivate() is set, then the page is not freeable */
         if (PagePrivate(page))
                 return 0;
diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 6bd19d843af7..df101d9f546a 100644
--- a/fs/nfs/nfsroot.c
+++ b/fs/nfs/nfsroot.c
@@ -105,7 +105,7 @@ static char nfs_root_name[256] __initdata = "";
 static __be32 servaddr __initdata = 0;
 
 /* Name of directory to mount */
-static char nfs_export_path[NFS_MAXPATHLEN] __initdata = { 0, };
+static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = { 0, };
 
 /* NFS-related data */
 static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 91679e2631ee..bb72ad34d51d 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -222,7 +222,7 @@ static void nfs_end_page_writeback(struct page *page)
                 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
 }
 
-static struct nfs_page *nfs_find_and_lock_request(struct page *page)
+static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
 {
         struct inode *inode = page->mapping->host;
         struct nfs_page *req;
@@ -241,7 +241,10 @@ static struct nfs_page *nfs_find_and_lock_request(struct page *page)
                  *       request as dirty (in which case we don't care).
                  */
                 spin_unlock(&inode->i_lock);
-                ret = nfs_wait_on_request(req);
+                if (!nonblock)
+                        ret = nfs_wait_on_request(req);
+                else
+                        ret = -EAGAIN;
                 nfs_release_request(req);
                 if (ret != 0)
                         return ERR_PTR(ret);
@@ -256,12 +259,12 @@ static struct nfs_page *nfs_find_and_lock_request(struct page *page)
  * May return an error if the user signalled nfs_wait_on_request().
  */
 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
-                                struct page *page)
+                                struct page *page, bool nonblock)
 {
         struct nfs_page *req;
         int ret = 0;
 
-        req = nfs_find_and_lock_request(page);
+        req = nfs_find_and_lock_request(page, nonblock);
         if (!req)
                 goto out;
         ret = PTR_ERR(req);
@@ -283,12 +286,20 @@ out:
 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
 {
         struct inode *inode = page->mapping->host;
+        int ret;
 
         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 
         nfs_pageio_cond_complete(pgio, page->index);
-        return nfs_page_async_flush(pgio, page);
+        ret = nfs_page_async_flush(pgio, page,
+                        wbc->sync_mode == WB_SYNC_NONE ||
+                        wbc->nonblocking != 0);
+        if (ret == -EAGAIN) {
+                redirty_page_for_writepage(wbc, page);
+                ret = 0;
+        }
+        return ret;
 }
 
 /*
@@ -1379,7 +1390,7 @@ static const struct rpc_call_ops nfs_commit_ops = {
         .rpc_release = nfs_commit_release,
 };
 
-static int nfs_commit_inode(struct inode *inode, int how)
+int nfs_commit_inode(struct inode *inode, int how)
 {
         LIST_HEAD(head);
         int may_wait = how & FLUSH_SYNC;
@@ -1443,7 +1454,7 @@ out_mark_dirty:
         return ret;
 }
 #else
-static int nfs_commit_inode(struct inode *inode, int how)
+int nfs_commit_inode(struct inode *inode, int how)
 {
         return 0;
 }
@@ -1546,7 +1557,7 @@ int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
 
         nfs_fscache_release_page(page, GFP_KERNEL);
 
-        req = nfs_find_and_lock_request(page);
+        req = nfs_find_and_lock_request(page, false);
         ret = PTR_ERR(req);
         if (IS_ERR(req))
                 goto out;