make d_splice_alias(ERR_PTR(err), dentry) = ERR_PTR(err)

... and simplify the living hell out of callers
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/btrfs/inode.c

@@ -4079,13 +4079,7 @@ static int btrfs_dentry_delete(const struct dentry *dentry)
 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
 				   struct nameidata *nd)
 {
-	struct inode *inode;
-
-	inode = btrfs_lookup_dentry(dir, dentry);
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-
-	return d_splice_alias(inode, dentry);
+	return d_splice_alias(btrfs_lookup_dentry(dir, dentry), dentry);
 }
 
 unsigned char btrfs_filetype_table[] = {

fs/dcache.c

@@ -1652,6 +1652,9 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
 {
 	struct dentry *new = NULL;
 
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+
 	if (inode && S_ISDIR(inode->i_mode)) {
 		spin_lock(&inode->i_lock);
 		new = __d_find_alias(inode, 1);

fs/efs/namei.c

@@ -60,14 +60,11 @@ static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len)
 
 struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) {
 	efs_ino_t inodenum;
-	struct inode * inode = NULL;
+	struct inode *inode = NULL;
 
 	inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
-	if (inodenum) {
+	if (inodenum)
 		inode = efs_iget(dir->i_sb, inodenum);
-		if (IS_ERR(inode))
-			return ERR_CAST(inode);
-	}
 
 	return d_splice_alias(inode, dentry);
 }

fs/exofs/namei.c

@@ -55,12 +55,7 @@ static struct dentry *exofs_lookup(struct inode *dir, struct dentry *dentry,
 		return ERR_PTR(-ENAMETOOLONG);
 
 	ino = exofs_inode_by_name(dir, dentry);
-	inode = NULL;
-	if (ino) {
-		inode = exofs_iget(dir->i_sb, ino);
-		if (IS_ERR(inode))
-			return ERR_CAST(inode);
-	}
+	inode = ino ? exofs_iget(dir->i_sb, ino) : NULL;
 	return d_splice_alias(inode, dentry);
 }
 

fs/ext2/namei.c

@@ -67,15 +67,11 @@ static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, str
 	inode = NULL;
 	if (ino) {
 		inode = ext2_iget(dir->i_sb, ino);
-		if (IS_ERR(inode)) {
-			if (PTR_ERR(inode) == -ESTALE) {
+		if (inode == ERR_PTR(-ESTALE)) {
 			ext2_error(dir->i_sb, __func__,
 					"deleted inode referenced: %lu",
 					(unsigned long) ino);
 			return ERR_PTR(-EIO);
-			} else {
-				return ERR_CAST(inode);
-			}
 		}
 	}
 	return d_splice_alias(inode, dentry);

fs/ext3/namei.c

@@ -1038,15 +1038,11 @@ static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry, str
 			return ERR_PTR(-EIO);
 		}
 		inode = ext3_iget(dir->i_sb, ino);
-		if (IS_ERR(inode)) {
-			if (PTR_ERR(inode) == -ESTALE) {
+		if (inode == ERR_PTR(-ESTALE)) {
 			ext3_error(dir->i_sb, __func__,
 					"deleted inode referenced: %lu",
 					ino);
 			return ERR_PTR(-EIO);
-			} else {
-				return ERR_CAST(inode);
-			}
 		}
 	}
 	return d_splice_alias(inode, dentry);

fs/ext4/namei.c

@@ -1037,15 +1037,11 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, stru
 			return ERR_PTR(-EIO);
 		}
 		inode = ext4_iget(dir->i_sb, ino);
-		if (IS_ERR(inode)) {
-			if (PTR_ERR(inode) == -ESTALE) {
+		if (inode == ERR_PTR(-ESTALE)) {
 			EXT4_ERROR_INODE(dir,
 					 "deleted inode referenced: %u",
 					 ino);
 			return ERR_PTR(-EIO);
-			} else {
-				return ERR_CAST(inode);
-			}
 		}
 	}
 	return d_splice_alias(inode, dentry);

fs/fat/namei_msdos.c

@@ -209,29 +209,20 @@ static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
 	int err;
 
 	lock_super(sb);
-
 	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
-	if (err) {
-		if (err == -ENOENT) {
+	switch (err) {
+	case -ENOENT:
 		inode = NULL;
-			goto out;
-		}
-		goto error;
-	}
-
+		break;
+	case 0:
 		inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 		brelse(sinfo.bh);
-	if (IS_ERR(inode)) {
-		err = PTR_ERR(inode);
-		goto error;
+		break;
+	default:
+		inode = ERR_PTR(err);
 	}
-out:
 	unlock_super(sb);
 	return d_splice_alias(inode, dentry);
-
-error:
-	unlock_super(sb);
-	return ERR_PTR(err);
 }
 
 /***** Creates a directory entry (name is already formatted). */

fs/isofs/namei.c

@@ -183,14 +183,9 @@ struct dentry *isofs_lookup(struct inode *dir, struct dentry *dentry, struct nam
 				1024 + page_address(page));
 	__free_page(page);
 
-	inode = NULL;
-	if (found) {
-		inode = isofs_iget(dir->i_sb, block, offset);
-		if (IS_ERR(inode)) {
-			mutex_unlock(&sbi->s_mutex);
-			return ERR_CAST(inode);
-		}
-	}
+	inode = found ? isofs_iget(dir->i_sb, block, offset) : NULL;
+
 	mutex_unlock(&sbi->s_mutex);
+
 	return d_splice_alias(inode, dentry);
 }

fs/jffs2/dir.c

@@ -102,10 +102,8 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target,
 	mutex_unlock(&dir_f->sem);
 	if (ino) {
 		inode = jffs2_iget(dir_i->i_sb, ino);
-		if (IS_ERR(inode)) {
+		if (IS_ERR(inode))
 			printk(KERN_WARNING "iget() failed for ino #%u\n", ino);
-			return ERR_CAST(inode);
-		}
 	}
 
 	return d_splice_alias(inode, target);

fs/jfs/namei.c

@@ -1481,10 +1481,8 @@ static struct dentry *jfs_lookup(struct inode *dip, struct dentry *dentry, struc
 	}
 
 	ip = jfs_iget(dip->i_sb, inum);
-	if (IS_ERR(ip)) {
+	if (IS_ERR(ip))
 		jfs_err("jfs_lookup: iget failed on inum %d", (uint) inum);
-		return ERR_CAST(ip);
-	}
 
 	return d_splice_alias(ip, dentry);
 }

fs/logfs/dir.c

@@ -371,11 +371,9 @@ static struct dentry *logfs_lookup(struct inode *dir, struct dentry *dentry,
 	page_cache_release(page);
 
 	inode = logfs_iget(dir->i_sb, ino);
-	if (IS_ERR(inode)) {
+	if (IS_ERR(inode))
 		printk(KERN_ERR"LogFS: Cannot read inode #%llx for dentry (%lx, %lx)n",
 				ino, dir->i_ino, index);
-		return ERR_CAST(inode);
-	}
 	return d_splice_alias(inode, dentry);
 }
 

fs/nilfs2/namei.c

@@ -72,12 +72,7 @@ nilfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 		return ERR_PTR(-ENAMETOOLONG);
 
 	ino = nilfs_inode_by_name(dir, &dentry->d_name);
-	inode = NULL;
-	if (ino) {
-		inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino);
-		if (IS_ERR(inode))
-			return ERR_CAST(inode);
-	}
+	inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
 	return d_splice_alias(inode, dentry);
 }
 

fs/squashfs/namei.c

@@ -220,11 +220,6 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
 					blk, off, ino_num);
 
 				inode = squashfs_iget(dir->i_sb, ino, ino_num);
-				if (IS_ERR(inode)) {
-					err = PTR_ERR(inode);
-					goto failed;
-				}
-
 				goto exit_lookup;
 			}
 		}

fs/ufs/namei.c

@@ -59,8 +59,6 @@ static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, stru
 	if (ino)
 		inode = ufs_iget(dir->i_sb, ino);
 	unlock_ufs(dir->i_sb);
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
 	return d_splice_alias(inode, dentry);
 }