[PATCH] libext2fs: don't truncate the orphan file inode if it is newly allocated

[PATCH] libext2fs: don't truncate the orphan file inode if it is newly allocated

[Theodore Ts'o]

In ext2fs_create_orphan_file(), don't try truncating inode for the
orphan file if ext2fs_create_orphan_file() allocated the inode.  This
avoids problems where the newly allocated inode in the inode table
might contain garbage; if the metadata checksum feature is enabled,
this will generally result in the function failing with a checksum
invalid error, but this can cause mke2fs (which calls
ext2fs_create_orphan_file) to fail.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 lib/ext2fs/orphan.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/lib/ext2fs/orphan.c b/lib/ext2fs/orphan.c
index e25f20ca2..c2f83567f 100644
--- a/lib/ext2fs/orphan.c
+++ b/lib/ext2fs/orphan.c
@@ -127,22 +127,21 @@ errcode_t ext2fs_create_orphan_file(ext2_filsys fs, blk_t num_blocks)
 	struct mkorphan_info oi;
 	struct ext4_orphan_block_tail *ob_tail;
 
-	if (!ino) {
+	if (ino) {
+		err = ext2fs_read_inode(fs, ino, &inode);
+		if (err)
+			return err;
+		if (EXT2_I_SIZE(&inode)) {
+			err = ext2fs_truncate_orphan_file(fs);
+			if (err)
+				return err;
+		}
+	} else {
 		err = ext2fs_new_inode(fs, EXT2_ROOT_INO, LINUX_S_IFREG | 0600,
 				       0, &ino);
 		if (err)
 			return err;
 		ext2fs_inode_alloc_stats2(fs, ino, +1, 0);
-		ext2fs_mark_ib_dirty(fs);
-	}
-
-	err = ext2fs_read_inode(fs, ino, &inode);
-	if (err)
-		return err;
-	if (EXT2_I_SIZE(&inode)) {
-		err = ext2fs_truncate_orphan_file(fs);
-		if (err)
-			return err;
 	}
 
 	memset(&inode, 0, sizeof(struct ext2_inode));
-- 
2.31.0

Re: [PATCH] libext2fs: don't truncate the orphan file inode if it is newly allocated

[Eric Whitney]

* Theodore Ts'o <tytso@mit.edu>:
> In ext2fs_create_orphan_file(), don't try truncating inode for the
> orphan file if ext2fs_create_orphan_file() allocated the inode.  This
> avoids problems where the newly allocated inode in the inode table
> might contain garbage; if the metadata checksum feature is enabled,
> this will generally result in the function failing with a checksum
> invalid error, but this can cause mke2fs (which calls
> ext2fs_create_orphan_file) to fail.
> 
> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
> ---
>  lib/ext2fs/orphan.c | 21 ++++++++++-----------
>  1 file changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/lib/ext2fs/orphan.c b/lib/ext2fs/orphan.c
> index e25f20ca2..c2f83567f 100644
> --- a/lib/ext2fs/orphan.c
> +++ b/lib/ext2fs/orphan.c
> @@ -127,22 +127,21 @@ errcode_t ext2fs_create_orphan_file(ext2_filsys fs, blk_t num_blocks)
>  	struct mkorphan_info oi;
>  	struct ext4_orphan_block_tail *ob_tail;
>  
> -	if (!ino) {
> +	if (ino) {
> +		err = ext2fs_read_inode(fs, ino, &inode);
> +		if (err)
> +			return err;
> +		if (EXT2_I_SIZE(&inode)) {
> +			err = ext2fs_truncate_orphan_file(fs);
> +			if (err)
> +				return err;
> +		}
> +	} else {
>  		err = ext2fs_new_inode(fs, EXT2_ROOT_INO, LINUX_S_IFREG | 0600,
>  				       0, &ino);
>  		if (err)
>  			return err;
>  		ext2fs_inode_alloc_stats2(fs, ino, +1, 0);
> -		ext2fs_mark_ib_dirty(fs);
> -	}
> -
> -	err = ext2fs_read_inode(fs, ino, &inode);
> -	if (err)
> -		return err;
> -	if (EXT2_I_SIZE(&inode)) {
> -		err = ext2fs_truncate_orphan_file(fs);
> -		if (err)
> -			return err;
>  	}
>  
>  	memset(&inode, 0, sizeof(struct ext2_inode));
> -- 
> 2.31.0
> 

With this patch to mke2fs, I ran ext4/049 on a 6.5 kernel using kvm-xfstests'
4k test scenario.  It passed 110/110 trials.  Without the patch, it fails
100% of the time.  So, it addresses the failures I've been seeing.

Thanks!

Tested-by: Eric Whitney <enwlinux@gmail.com>