Re: git: 45d4e82bf61f - main - msdosfs: fix cluster limit when mounting FAT-16 file systems

Van: "Stefan Eßer" <se@FreeBSD.org>
Datum: 9 augustus 2024 19:33
Aan: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Onderwerp: git: 45d4e82bf61f - main - msdosfs: fix cluster limit when  mounting FAT-16 file systems

> 
> 
> The branch main has been updated by se:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=45d4e82bf61f91792142a2b9e2af657dab8500fd
> 
> commit 45d4e82bf61f91792142a2b9e2af657dab8500fd
> Author:     Stefan Eßer 
> AuthorDate: 2024-08-09 17:26:27 +0000
> Commit:     Stefan Eßer 
> CommitDate: 2024-08-09 17:26:27 +0000
> 
>     msdosfs: fix cluster limit when mounting FAT-16 file systems
>     
>     The maximum cluster number was calculated based on the number of data
>     cluters that fit in the givem partition size and the size of the FAT
>     area. This limit did not take into account that the highest 10 cluster
>     numbers are reserved and must not be used for files.
>     
>     PR:             280347
>     MFC after:      3 days
>     Reported by:    pho@FreeBSD.org
> ---
>  sys/fs/msdosfs/msdosfs_vfsops.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/sys/fs/msdosfs/msdosfs_vfsops.c b/sys/fs/msdosfs/msdosfs_vfsops.c
> index 258c701bd300..adcffe45df82 100644
> --- a/sys/fs/msdosfs/msdosfs_vfsops.c
> +++ b/sys/fs/msdosfs/msdosfs_vfsops.c
> @@ -722,7 +722,9 @@ mountmsdosfs(struct vnode *odevvp, struct mount *mp)
>         }
>     }
>  
> -   clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv ;
> +   clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
> +   if (clusters >= (CLUST_RSRVD & pmp->pm_fatmask))
> +       clusters = CLUST_RSRVD & pmp->pm_fatmask;
>     if (pmp->pm_maxcluster >= clusters) {
>  #ifdef MSDOSFS_DEBUG
>         printf("Warning: number of clusters (%ld) exceeds FAT "
> 
> 
> 
> 
> 


Hi,
Isn’t this similar? And a little bit shorter. 
clusters = MIN(clusters, CLUST_RSRVD & pmp->pm_fatmask);

Regards,Ronald