cleanup d_add_ci

Make sure that comments describe what's going on and not how, and always use __d_instantiate instead of two separate branches, one with d_instantiate and one with __d_instantiate. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

cleanup d_add_ci
Make sure that comments describe what's going on and not how, and always use __d_instantiate instead of two separate branches, one with d_instantiate and one with __d_instantiate. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Christoph Hellwig · Al Viro
1 parent 2b1c6bd77d
Showing 1 changed file with 18 additions and 30 deletions Side-by-side Diff
fs/dcache.c
@@ -1247,15 +1247,18 @@
 	struct dentry *found;
 	struct dentry *new;
  
-	/* Does a dentry matching the name exist already? */
+	/*
+	 * First check if a dentry matching the name already exists,
+	 * if not go ahead and create it now.
+	 */
 	found = d_hash_and_lookup(dentry->d_parent, name);
-	/* If not, create it now and return */
 	if (!found) {
 		new = d_alloc(dentry->d_parent, name);
 		if (!new) {
 			error = -ENOMEM;
 			goto err_out;
 		}
+
 		found = d_splice_alias(inode, new);
 		if (found) {
 			dput(new);
  
  
  
  
  
  
  
  
  
  
  
  
@@ -1263,61 +1266,46 @@
 		}
 		return new;
 	}
-	/* Matching dentry exists, check if it is negative. */
+
+	/*
+	 * If a matching dentry exists, and it's not negative use it.
+	 *
+	 * Decrement the reference count to balance the iget() done
+	 * earlier on.
+	 */
 	if (found->d_inode) {
 		if (unlikely(found->d_inode != inode)) {
 			/* This can't happen because bad inodes are unhashed. */
 			BUG_ON(!is_bad_inode(inode));
 			BUG_ON(!is_bad_inode(found->d_inode));
 		}
-		/*
-		 * Already have the inode and the dentry attached, decrement
-		 * the reference count to balance the iget() done
-		 * earlier on.  We found the dentry using d_lookup() so it
-		 * cannot be disconnected and thus we do not need to worry
-		 * about any NFS/disconnectedness issues here.
-		 */
 		iput(inode);
 		return found;
 	}
+
 	/*
 	 * Negative dentry: instantiate it unless the inode is a directory and
-	 * has a 'disconnected' dentry (i.e. IS_ROOT and DCACHE_DISCONNECTED),
-	 * in which case d_move() that in place of the found dentry.
+	 * already has a dentry.
 	 */
-	if (!S_ISDIR(inode->i_mode)) {
-		/* Not a directory; everything is easy. */
-		d_instantiate(found, inode);
-		return found;
-	}
 	spin_lock(&dcache_lock);
-	if (list_empty(&inode->i_dentry)) {
-		/*
-		 * Directory without a 'disconnected' dentry; we need to do
-		 * d_instantiate() by hand because it takes dcache_lock which
-		 * we already hold.
-		 */
+	if (!S_ISDIR(inode->i_mode) || list_empty(&inode->i_dentry)) {
 		__d_instantiate(found, inode);
 		spin_unlock(&dcache_lock);
 		security_d_instantiate(found, inode);
 		return found;
 	}
+
 	/*
-	 * Directory with a 'disconnected' dentry; get a reference to the
-	 * 'disconnected' dentry.
+	 * In case a directory already has a (disconnected) entry grab a
+	 * reference to it, move it in place and use it.
 	 */
 	new = list_entry(inode->i_dentry.next, struct dentry, d_alias);
 	dget_locked(new);
 	spin_unlock(&dcache_lock);
-	/* Do security vodoo. */
 	security_d_instantiate(found, inode);
-	/* Move new in place of found. */
 	d_move(new, found);
-	/* Balance the iget() we did above. */
 	iput(inode);
-	/* Throw away found. */
 	dput(found);
-	/* Use new as the actual dentry. */
 	return new;
  
 err_out:
...	...	@@ -1247,15 +1247,18 @@
1247	1247	struct dentry *found;
1248	1248	struct dentry *new;
1249	1249
1250		- /* Does a dentry matching the name exist already? */
	1250	+ /*
	1251	+ * First check if a dentry matching the name already exists,
	1252	+ * if not go ahead and create it now.
	1253	+ */
1251	1254	found = d_hash_and_lookup(dentry->d_parent, name);
1252		- /* If not, create it now and return */
1253	1255	if (!found) {
1254	1256	new = d_alloc(dentry->d_parent, name);
1255	1257	if (!new) {
1256	1258	error = -ENOMEM;
1257	1259	goto err_out;
1258	1260	}
	1261	+
1259	1262	found = d_splice_alias(inode, new);
1260	1263	if (found) {
1261	1264	dput(new);
1262	1265
1263	1266
1264	1267
1265	1268
1266	1269
1267	1270
1268	1271
1269	1272
1270	1273
1271	1274
1272	1275
1273	1276
...	...	@@ -1263,61 +1266,46 @@
1263	1266	}
1264	1267	return new;
1265	1268	}
1266		- /* Matching dentry exists, check if it is negative. */
	1269	+
	1270	+ /*
	1271	+ * If a matching dentry exists, and it's not negative use it.
	1272	+ *
	1273	+ * Decrement the reference count to balance the iget() done
	1274	+ * earlier on.
	1275	+ */
1267	1276	if (found->d_inode) {
1268	1277	if (unlikely(found->d_inode != inode)) {
1269	1278	/* This can't happen because bad inodes are unhashed. */
1270	1279	BUG_ON(!is_bad_inode(inode));
1271	1280	BUG_ON(!is_bad_inode(found->d_inode));
1272	1281	}
1273		- /*
1274		- * Already have the inode and the dentry attached, decrement
1275		- * the reference count to balance the iget() done
1276		- * earlier on. We found the dentry using d_lookup() so it
1277		- * cannot be disconnected and thus we do not need to worry
1278		- * about any NFS/disconnectedness issues here.
1279		- */
1280	1282	iput(inode);
1281	1283	return found;
1282	1284	}
	1285	+
1283	1286	/*
1284	1287	* Negative dentry: instantiate it unless the inode is a directory and
1285		- * has a 'disconnected' dentry (i.e. IS_ROOT and DCACHE_DISCONNECTED),
1286		- * in which case d_move() that in place of the found dentry.
	1288	+ * already has a dentry.
1287	1289	*/
1288		- if (!S_ISDIR(inode->i_mode)) {
1289		- /* Not a directory; everything is easy. */
1290		- d_instantiate(found, inode);
1291		- return found;
1292		- }
1293	1290	spin_lock(&dcache_lock);
1294		- if (list_empty(&inode->i_dentry)) {
1295		- /*
1296		- * Directory without a 'disconnected' dentry; we need to do
1297		- * d_instantiate() by hand because it takes dcache_lock which
1298		- * we already hold.
1299		- */
	1291	+ if (!S_ISDIR(inode->i_mode) \|\| list_empty(&inode->i_dentry)) {
1300	1292	__d_instantiate(found, inode);
1301	1293	spin_unlock(&dcache_lock);
1302	1294	security_d_instantiate(found, inode);
1303	1295	return found;
1304	1296	}
	1297	+
1305	1298	/*
1306		- * Directory with a 'disconnected' dentry; get a reference to the
1307		- * 'disconnected' dentry.
	1299	+ * In case a directory already has a (disconnected) entry grab a
	1300	+ * reference to it, move it in place and use it.
1308	1301	*/
1309	1302	new = list_entry(inode->i_dentry.next, struct dentry, d_alias);
1310	1303	dget_locked(new);
1311	1304	spin_unlock(&dcache_lock);
1312		- /* Do security vodoo. */
1313	1305	security_d_instantiate(found, inode);
1314		- /* Move new in place of found. */
1315	1306	d_move(new, found);
1316		- /* Balance the iget() we did above. */
1317	1307	iput(inode);
1318		- /* Throw away found. */
1319	1308	dput(found);
1320		- /* Use new as the actual dentry. */
1321	1309	return new;
1322	1310
1323	1311	err_out: