Re: [PATCH] ext2: add missing brelse() in ext2_iget()

[Jan Kara <jack@suse.cz>]

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On Sun 16-06-19 09:45:21, Darrick J. Wong wrote:
> On Sun, Jun 16, 2019 at 11:08:01PM +0800, Chengguang Xu wrote:
> > Add missing brelse() on error path of ext2_iget().
> > 
> > Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
> 
> /me wonders if the brelse ought to be moved down to bad_inode so that
> each error branch only has to set @ret and then jump (thereby
> eliminating the possibility of making this mistake again), but for a
> oneliner quick fix I guess it's fine:
> 
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

I've applied the fix and also the cleanup Darrick suggested (attached).

								Honza
> 
> --D
> 
> > ---
> >  fs/ext2/inode.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
> > index e474127dd255..fb3611f02051 100644
> > --- a/fs/ext2/inode.c
> > +++ b/fs/ext2/inode.c
> > @@ -1473,6 +1473,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
> >  	else
> >  		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
> >  	if (i_size_read(inode) < 0) {
> > +		brelse(bh);
> >  		ret = -EFSCORRUPTED;
> >  		goto bad_inode;
> >  	}
> > -- 
> > 2.21.0
> > 
> > 
> > 
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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From 936bbf3aea84696ce1081ab9648d08bbf08ca7aa Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Wed, 19 Jun 2019 18:29:45 +0200
Subject: [PATCH] ext2: Always brelse bh on failure in ext2_iget()

All but one bail out paths in ext2_iget() is releasing bh. Move the
releasing of bh into a common error handling code.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ext2/inode.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index e680478866db..7004ce581a32 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1400,7 +1400,7 @@ void ext2_set_file_ops(struct inode *inode)
 struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 {
 	struct ext2_inode_info *ei;
-	struct buffer_head * bh;
+	struct buffer_head * bh = NULL;
 	struct ext2_inode *raw_inode;
 	struct inode *inode;
 	long ret = -EIO;
@@ -1446,7 +1446,6 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 	 */
 	if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
 		/* this inode is deleted */
-		brelse (bh);
 		ret = -ESTALE;
 		goto bad_inode;
 	}
@@ -1463,7 +1462,6 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 	    !ext2_data_block_valid(EXT2_SB(sb), ei->i_file_acl, 1)) {
 		ext2_error(sb, "ext2_iget", "bad extended attribute block %u",
 			   ei->i_file_acl);
-		brelse(bh);
 		ret = -EFSCORRUPTED;
 		goto bad_inode;
 	}
@@ -1473,7 +1471,6 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 	else
 		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
 	if (i_size_read(inode) < 0) {
-		brelse(bh);
 		ret = -EFSCORRUPTED;
 		goto bad_inode;
 	}
@@ -1527,6 +1524,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 	return inode;
 	
 bad_inode:
+	brelse(bh);
 	iget_failed(inode);
 	return ERR_PTR(ret);
 }
-- 
2.16.4