From 1056008226769fe982236c26038a095aeb47714b Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Fri, 29 Aug 2014 20:51:32 -0400
Subject: [PATCH] ext4: convert ext4_getblk() to use the ERR_PTR convention

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/ext4.h  |  3 +--
 fs/ext4/inode.c | 51 ++++++++++++++++++++++++-------------------------
 fs/ext4/namei.c |  9 ++++-----
 3 files changed, 30 insertions(+), 33 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b0c225cdb52c..8009077079e4 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2086,8 +2086,7 @@ extern int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
 extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);
 
 /* inode.c */
-struct buffer_head *ext4_getblk(handle_t *, struct inode *,
-						ext4_lblk_t, int, int *);
+struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int);
 struct buffer_head *ext4_bread(handle_t *, struct inode *,
 						ext4_lblk_t, int, int *);
 int ext4_get_block_write(struct inode *inode, sector_t iblock,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3aa26e9117c4..0dfc1cd1eb52 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -734,11 +734,11 @@ int ext4_get_block(struct inode *inode, sector_t iblock,
  * `handle' can be NULL if create is zero
  */
 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
-				ext4_lblk_t block, int create, int *errp)
+				ext4_lblk_t block, int create)
 {
 	struct ext4_map_blocks map;
 	struct buffer_head *bh;
-	int fatal = 0, err;
+	int err;
 
 	J_ASSERT(handle != NULL || create == 0);
 
@@ -747,21 +747,14 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 	err = ext4_map_blocks(handle, inode, &map,
 			      create ? EXT4_GET_BLOCKS_CREATE : 0);
 
-	/* ensure we send some value back into *errp */
-	*errp = 0;
-
-	if (create && err == 0)
-		err = -ENOSPC;	/* should never happen */
+	if (err == 0)
+		return create ? ERR_PTR(-ENOSPC) : NULL;
 	if (err < 0)
-		*errp = err;
-	if (err <= 0)
-		return NULL;
+		return ERR_PTR(err);
 
 	bh = sb_getblk(inode->i_sb, map.m_pblk);
-	if (unlikely(!bh)) {
-		*errp = -ENOMEM;
-		return NULL;
-	}
+	if (unlikely(!bh))
+		return ERR_PTR(-ENOMEM);
 	if (map.m_flags & EXT4_MAP_NEW) {
 		J_ASSERT(create != 0);
 		J_ASSERT(handle != NULL);
@@ -775,25 +768,26 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 		 */
 		lock_buffer(bh);
 		BUFFER_TRACE(bh, "call get_create_access");
-		fatal = ext4_journal_get_create_access(handle, bh);
-		if (!fatal && !buffer_uptodate(bh)) {
+		err = ext4_journal_get_create_access(handle, bh);
+		if (unlikely(err)) {
+			unlock_buffer(bh);
+			goto errout;
+		}
+		if (!buffer_uptodate(bh)) {
 			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
 			set_buffer_uptodate(bh);
 		}
 		unlock_buffer(bh);
 		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
 		err = ext4_handle_dirty_metadata(handle, inode, bh);
-		if (!fatal)
-			fatal = err;
-	} else {
+		if (unlikely(err))
+			goto errout;
+	} else
 		BUFFER_TRACE(bh, "not a new buffer");
-	}
-	if (fatal) {
-		*errp = fatal;
-		brelse(bh);
-		bh = NULL;
-	}
 	return bh;
+errout:
+	brelse(bh);
+	return ERR_PTR(err);
 }
 
 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
@@ -801,7 +795,12 @@ struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
 {
 	struct buffer_head *bh;
 
-	bh = ext4_getblk(handle, inode, block, create, err);
+	*err = 0;
+	bh = ext4_getblk(handle, inode, block, create);
+	if (IS_ERR(bh)) {
+		*err = PTR_ERR(bh);
+		return NULL;
+	}
 	if (!bh)
 		return bh;
 	if (buffer_uptodate(bh))
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 1421ec1cd7e4..26f114b1e4d6 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1226,8 +1226,7 @@ static struct buffer_head * ext4_find_entry (struct inode *dir,
 				   buffer */
 	int num = 0;
 	ext4_lblk_t  nblocks;
-	int i, err = 0;
-	int namelen;
+	int i, namelen;
 
 	*res_dir = NULL;
 	sb = dir->i_sb;
@@ -1293,10 +1292,10 @@ static struct buffer_head * ext4_find_entry (struct inode *dir,
 					break;
 				}
 				num++;
-				bh = ext4_getblk(NULL, dir, b++, 0, &err);
-				if (unlikely(err)) {
+				bh = ext4_getblk(NULL, dir, b++, 0);
+				if (unlikely(IS_ERR(bh))) {
 					if (ra_max == 0)
-						return ERR_PTR(err);
+						return bh;
 					break;
 				}
 				bh_use[ra_max] = bh;
-- 
2.45.2