Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux.git] / fs / nfs / dir.c

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index b4e7558e42ab9c5fd6e417f37fb54d1d07473d3e..193d6fb363b7434ae629fc48992812a198b47ec3 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -986,14 +986,113 @@ static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end,
  * full lookup on all child dentries of 'dir' whenever a change occurs
  * on the server that might have invalidated our dcache.
  *
+ * Note that we reserve bit '0' as a tag to let us know when a dentry
+ * was revalidated while holding a delegation on its inode.
+ *
  * The caller should be holding dir->i_lock
  */
 void nfs_force_lookup_revalidate(struct inode *dir)
 {
-       NFS_I(dir)->cache_change_attribute++;
+       NFS_I(dir)->cache_change_attribute += 2;
 }
 EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate);
 
+/**
+ * nfs_verify_change_attribute - Detects NFS remote directory changes
+ * @dir: pointer to parent directory inode
+ * @verf: previously saved change attribute
+ *
+ * Return "false" if the verifiers doesn't match the change attribute.
+ * This would usually indicate that the directory contents have changed on
+ * the server, and that any dentries need revalidating.
+ */
+static bool nfs_verify_change_attribute(struct inode *dir, unsigned long verf)
+{
+       return (verf & ~1UL) == nfs_save_change_attribute(dir);
+}
+
+static void nfs_set_verifier_delegated(unsigned long *verf)
+{
+       *verf |= 1UL;
+}
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+static void nfs_unset_verifier_delegated(unsigned long *verf)
+{
+       *verf &= ~1UL;
+}
+#endif /* IS_ENABLED(CONFIG_NFS_V4) */
+
+static bool nfs_test_verifier_delegated(unsigned long verf)
+{
+       return verf & 1;
+}
+
+static bool nfs_verifier_is_delegated(struct dentry *dentry)
+{
+       return nfs_test_verifier_delegated(dentry->d_time);
+}
+
+static void nfs_set_verifier_locked(struct dentry *dentry, unsigned long verf)
+{
+       struct inode *inode = d_inode(dentry);
+
+       if (!nfs_verifier_is_delegated(dentry) &&
+           !nfs_verify_change_attribute(d_inode(dentry->d_parent), verf))
+               goto out;
+       if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
+               nfs_set_verifier_delegated(&verf);
+out:
+       dentry->d_time = verf;
+}
+
+/**
+ * nfs_set_verifier - save a parent directory verifier in the dentry
+ * @dentry: pointer to dentry
+ * @verf: verifier to save
+ *
+ * Saves the parent directory verifier in @dentry. If the inode has
+ * a delegation, we also tag the dentry as having been revalidated
+ * while holding a delegation so that we know we don't have to
+ * look it up again after a directory change.
+ */
+void nfs_set_verifier(struct dentry *dentry, unsigned long verf)
+{
+
+       spin_lock(&dentry->d_lock);
+       nfs_set_verifier_locked(dentry, verf);
+       spin_unlock(&dentry->d_lock);
+}
+EXPORT_SYMBOL_GPL(nfs_set_verifier);
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+/**
+ * nfs_clear_verifier_delegated - clear the dir verifier delegation tag
+ * @inode: pointer to inode
+ *
+ * Iterates through the dentries in the inode alias list and clears
+ * the tag used to indicate that the dentry has been revalidated
+ * while holding a delegation.
+ * This function is intended for use when the delegation is being
+ * returned or revoked.
+ */
+void nfs_clear_verifier_delegated(struct inode *inode)
+{
+       struct dentry *alias;
+
+       if (!inode)
+               return;
+       spin_lock(&inode->i_lock);
+       hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
+               spin_lock(&alias->d_lock);
+               nfs_unset_verifier_delegated(&alias->d_time);
+               spin_unlock(&alias->d_lock);
+       }
+       spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL_GPL(nfs_clear_verifier_delegated);
+#endif /* IS_ENABLED(CONFIG_NFS_V4) */
+
 /*
  * A check for whether or not the parent directory has changed.
  * In the case it has, we assume that the dentries are untrustworthy
@@ -1235,7 +1334,7 @@ nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
                goto out_bad;
        }
 
-       if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ))
+       if (nfs_verifier_is_delegated(dentry))
                return nfs_lookup_revalidate_delegated(dir, dentry, inode);
 
        /* Force a full look up iff the parent directory has changed */
@@ -1675,7 +1774,7 @@ nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
        if (inode == NULL)
                goto full_reval;
 
-       if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ))
+       if (nfs_verifier_is_delegated(dentry))
                return nfs_lookup_revalidate_delegated(dir, dentry, inode);
 
        /* NFS only supports OPEN on regular files */