[PATCH] NFS: Cleanup of caching code, and slight optimization of writes.

 Unless we're doing O_APPEND writes, we really don't care about revalidating
 the file length. Just make sure that we catch any page cache invalidations.

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

2 files changed, 38 insertions, 18 deletions

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index a606708264ed..40436857ed42 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -333,9 +333,15 @@ nfs_file_write(struct kiocb *iocb, const char __user *buf, size_t count, loff_t
         result = -EBUSY;
         if (IS_SWAPFILE(inode))
                 goto out_swapfile;
-        result = nfs_revalidate_inode(NFS_SERVER(inode), inode);
-        if (result)
-                goto out;
+        /*
+         * O_APPEND implies that we must revalidate the file length.
+         */
+        if (iocb->ki_filp->f_flags & O_APPEND) {
+                result = nfs_revalidate_file_size(inode, iocb->ki_filp);
+                if (result)
+                        goto out;
+        } else
+                nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
 
         result = count;
         if (!count)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index b2d16758ced8..a3922f4cc0a8 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1062,21 +1062,7 @@ __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
         if (verifier == nfsi->cache_change_attribute)
                 nfsi->flags &= ~(NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME);
         /* Do the page cache invalidation */
-        if (flags & NFS_INO_INVALID_DATA) {
-                if (S_ISREG(inode->i_mode)) {
-                        if (filemap_fdatawrite(inode->i_mapping) == 0)
-                                filemap_fdatawait(inode->i_mapping);
-                        nfs_wb_all(inode);
-                }
-                nfsi->flags &= ~NFS_INO_INVALID_DATA;
-                invalidate_inode_pages2(inode->i_mapping);
-                memset(NFS_COOKIEVERF(inode), 0, sizeof(NFS_COOKIEVERF(inode)));
-                dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
-                                inode->i_sb->s_id,
-                                (long long)NFS_FILEID(inode));
-                /* This ensures we revalidate dentries */
-                nfsi->cache_change_attribute++;
-        }
+        nfs_revalidate_mapping(inode, inode->i_mapping);
         if (flags & NFS_INO_INVALID_ACL)
                 nfs_zap_acl_cache(inode);
         dfprintk(PAGECACHE, "NFS: (%s/%Ld) revalidation complete\n",
@@ -1116,6 +1102,34 @@ int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
 }
 
 /**
+ * nfs_revalidate_mapping - Revalidate the pagecache
+ * @inode - pointer to host inode
+ * @mapping - pointer to mapping
+ */
+void nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
+{
+        struct nfs_inode *nfsi = NFS_I(inode);
+
+        if (nfsi->flags & NFS_INO_INVALID_DATA) {
+                if (S_ISREG(inode->i_mode)) {
+                        if (filemap_fdatawrite(mapping) == 0)
+                                filemap_fdatawait(mapping);
+                        nfs_wb_all(inode);
+                }
+                invalidate_inode_pages2(mapping);
+                nfsi->flags &= ~NFS_INO_INVALID_DATA;
+                if (S_ISDIR(inode->i_mode)) {
+                        memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
+                        /* This ensures we revalidate child dentries */
+                        nfsi->cache_change_attribute++;
+                }
+                dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
+                                inode->i_sb->s_id,
+                                (long long)NFS_FILEID(inode));
+        }
+}
+
+/**
  * nfs_begin_data_update
  * @inode - pointer to inode
  * Declare that a set of operations will update file data on the server