2 files changed, 76 insertions, 15 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 73f96acd5d37..ff6155f5e8d9 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -528,19 +528,39 @@ static inline void nfs_renew_times(struct dentry * dentry)
         dentry->d_time = jiffies;
 }
 
+/*
+ * Return the intent data that applies to this particular path component
+ *
+ * Note that the current set of intents only apply to the very last
+ * component of the path.
+ * We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT.
+ */
+static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask)
+{
+        if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT))
+                return 0;
+        return nd->flags & mask;
+}
+
+/*
+ * Inode and filehandle revalidation for lookups.
+ *
+ * We force revalidation in the cases where the VFS sets LOOKUP_REVAL,
+ * or if the intent information indicates that we're about to open this
+ * particular file and the "nocto" mount flag is not set.
+ *
+ */
 static inline
 int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
 {
         struct nfs_server *server = NFS_SERVER(inode);
 
         if (nd != NULL) {
-                int ndflags = nd->flags;
                 /* VFS wants an on-the-wire revalidation */
-                if (ndflags & LOOKUP_REVAL)
+                if (nd->flags & LOOKUP_REVAL)
                         goto out_force;
                 /* This is an open(2) */
-                if ((ndflags & LOOKUP_OPEN) &&
-                                !(ndflags & LOOKUP_CONTINUE) &&
+                if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 &&
                                 !(server->flags & NFS_MOUNT_NOCTO))
                         goto out_force;
         }
@@ -560,12 +580,8 @@ static inline
 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
                        struct nameidata *nd)
 {
-        int ndflags = 0;
-
-        if (nd)
-                ndflags = nd->flags;
         /* Don't revalidate a negative dentry if we're creating a new file */
-        if ((ndflags & LOOKUP_CREATE) && !(ndflags & LOOKUP_CONTINUE))
+        if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0)
                 return 0;
         return !nfs_check_verifier(dir, dentry);
 }
@@ -700,12 +716,16 @@ struct dentry_operations nfs_dentry_operations = {
         .d_iput         = nfs_dentry_iput,
 };
 
+/*
+ * Use intent information to check whether or not we're going to do
+ * an O_EXCL create using this path component.
+ */
 static inline
 int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd)
 {
         if (NFS_PROTO(dir)->version == 2)
                 return 0;
-        if (!nd || (nd->flags & LOOKUP_CONTINUE) || !(nd->flags & LOOKUP_CREATE))
+        if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_CREATE) == 0)
                 return 0;
         return (nd->intent.open.flags & O_EXCL) != 0;
 }
@@ -772,12 +792,13 @@ struct dentry_operations nfs4_dentry_operations = {
         .d_iput         = nfs_dentry_iput,
 };
 
+/*
+ * Use intent information to determine whether we need to substitute
+ * the NFSv4-style stateful OPEN for the LOOKUP call
+ */
 static int is_atomic_open(struct inode *dir, struct nameidata *nd)
 {
-        if (!nd)
-                return 0;
-        /* Check that we are indeed trying to open this file */
-        if ((nd->flags & LOOKUP_CONTINUE) || !(nd->flags & LOOKUP_OPEN))
+        if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0)
                 return 0;
         /* NFS does not (yet) have a stateful open for directories */
         if (nd->flags & LOOKUP_DIRECTORY)
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index f06eee6dcff5..55c907592490 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -37,6 +37,7 @@
 
 static int nfs_file_open(struct inode *, struct file *);
 static int nfs_file_release(struct inode *, struct file *);
+static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
 static int  nfs_file_mmap(struct file *, struct vm_area_struct *);
 static ssize_t nfs_file_sendfile(struct file *, loff_t *, size_t, read_actor_t, void *);
 static ssize_t nfs_file_read(struct kiocb *, char __user *, size_t, loff_t);
@@ -48,7 +49,7 @@ static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
 
 struct file_operations nfs_file_operations = {
-        .llseek         = remote_llseek,
+        .llseek         = nfs_file_llseek,
         .read           = do_sync_read,
         .write          = do_sync_write,
         .aio_read               = nfs_file_read,
@@ -114,6 +115,45 @@ nfs_file_release(struct inode *inode, struct file *filp)
         return NFS_PROTO(inode)->file_release(inode, filp);
 }
 
+/**
+ * nfs_revalidate_size - Revalidate the file size
+ * @inode - pointer to inode struct
+ * @file - pointer to struct file
+ *
+ * Revalidates the file length. This is basically a wrapper around
+ * nfs_revalidate_inode() that takes into account the fact that we may
+ * have cached writes (in which case we don't care about the server's
+ * idea of what the file length is), or O_DIRECT (in which case we
+ * shouldn't trust the cache).
+ */
+static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
+{
+        struct nfs_server *server = NFS_SERVER(inode);
+        struct nfs_inode *nfsi = NFS_I(inode);
+
+        if (server->flags & NFS_MOUNT_NOAC)
+                goto force_reval;
+        if (filp->f_flags & O_DIRECT)
+                goto force_reval;
+        if (nfsi->npages != 0)
+                return 0;
+        return nfs_revalidate_inode(server, inode);
+force_reval:
+        return __nfs_revalidate_inode(server, inode);
+}
+
+static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
+{
+        /* origin == SEEK_END => we must revalidate the cached file length */
+        if (origin == 2) {
+                struct inode *inode = filp->f_mapping->host;
+                int retval = nfs_revalidate_file_size(inode, filp);
+                if (retval < 0)
+                        return (loff_t)retval;
+        }
+        return remote_llseek(filp, offset, origin);
+}
+
 /*
  * Flush all dirty pages, and check for write errors.
  *