Re: [PATCH] ext4: Do not destroy ext4_groupinfo_caches if ext4_mb_init() fails

["Lukáš Czerner" <lczerner@redhat.com>]

On Mon, 12 May 2014, Andrey Tsyvarev wrote:

> Date: Mon, 12 May 2014 12:23:59 +0400
> From: Andrey Tsyvarev <tsyvarev@ispras.ru>
> To: Theodore Ts'o <tytso@mit.edu>
> Cc: Andrey Tsyvarev <tsyvarev@ispras.ru>,
>     Andreas Dilger <adilger.kernel@dilger.ca>, linux-ext4@vger.kernel.org,
>     linux-kernel@vger.kernel.org, Alexey Khoroshilov <khoroshilov@ispras.ru>
> Subject: [PATCH] ext4: Do not destroy ext4_groupinfo_caches if ext4_mb_init()
>     fails
> 
> Caches from 'ext4_groupinfo_caches' may be in use by other mounts, which have already existed.
> So, it is incorrect to destroy them when newly requested mount fails.
> 
> Found by Linux File System Verification project (linuxtesting.org).

Makes sense, thanks! Can you please share the test case which
triggered this ? It might be worth including in xfstests.

Reviewed-by: Lukas Czerner <lczerner@redhat.com>

> 
> Signed-off-by: Andrey Tsyvarev <tsyvarev@ispras.ru>
> ---
>  fs/ext4/mballoc.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 04a5c75..becea1d 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2607,7 +2607,7 @@ int ext4_mb_init(struct super_block *sb)
>  	sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
>  	if (sbi->s_locality_groups == NULL) {
>  		ret = -ENOMEM;
> -		goto out_free_groupinfo_slab;
> +		goto out;
>  	}
>  	for_each_possible_cpu(i) {
>  		struct ext4_locality_group *lg;
> @@ -2632,8 +2632,6 @@ int ext4_mb_init(struct super_block *sb)
>  out_free_locality_groups:
>  	free_percpu(sbi->s_locality_groups);
>  	sbi->s_locality_groups = NULL;
> -out_free_groupinfo_slab:
> -	ext4_groupinfo_destroy_slabs();
>  out:
>  	kfree(sbi->s_mb_offsets);
>  	sbi->s_mb_offsets = NULL;
>