Re: [PATCH v5] xfs: fix the size of xfs_mode_to_ftype table

[Brian Foster <bfoster@redhat.com>]

On Sun, Dec 25, 2016 at 01:23:45PM +0200, Amir Goldstein wrote:
> Fix the size of the xfs_mode_to_ftype conversion table,
> which was too small to handle an invalid value of mode=S_IFMT.
> 
> Use a convenience macro S_DT(mode) to convert from
> mode to dirent file type and change the name of the table
> to xfs_dtype_to_ftype to correctly describe its index values.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/libxfs/xfs_dir2.c | 18 +++++++++---------
>  fs/xfs/libxfs/xfs_dir2.h |  4 +++-
>  fs/xfs/xfs_iops.c        |  2 +-
>  3 files changed, 13 insertions(+), 11 deletions(-)
> 
> Darrick,
> 
> I implemented the xfs specific test case to test all possible
> malformed file type values as you suggested and fixed up some minor
> nits that Brian pointed out.
> 
> Tested with generic/396 with -n ftype=0|1.
> Tested with new xfs/348 test with -n ftype=0|1.
> 
> Amir.
> 
> v5:
> - remove wrong argument about on-disk malformed mode from commit message
> - address Brian's review comments
> 
> v4:
> - independent fix patch for xfs
> 
> v3:
> - resort to simpler cleanup with macros DT_MAX and S_DT()
> - mention the minor bug fix in commit message
> 
> v2:
> - add private conversion from common to on-disk values
> 
> v1:
> - use common conversion functions to get on-disk values
> 
> diff --git a/fs/xfs/libxfs/xfs_dir2.c b/fs/xfs/libxfs/xfs_dir2.c
> index c58d72c..48d7c45 100644
> --- a/fs/xfs/libxfs/xfs_dir2.c
> +++ b/fs/xfs/libxfs/xfs_dir2.c
> @@ -41,15 +41,15 @@ struct xfs_name xfs_name_dotdot = { (unsigned char *)"..", 2, XFS_DIR3_FT_DIR };
>   * for file type specification. This will be propagated into the directory
>   * structure if appropriate for the given operation and filesystem config.
>   */
> -const unsigned char xfs_mode_to_ftype[S_IFMT >> S_SHIFT] = {
> -	[0]			= XFS_DIR3_FT_UNKNOWN,
> -	[S_IFREG >> S_SHIFT]    = XFS_DIR3_FT_REG_FILE,
> -	[S_IFDIR >> S_SHIFT]    = XFS_DIR3_FT_DIR,
> -	[S_IFCHR >> S_SHIFT]    = XFS_DIR3_FT_CHRDEV,
> -	[S_IFBLK >> S_SHIFT]    = XFS_DIR3_FT_BLKDEV,
> -	[S_IFIFO >> S_SHIFT]    = XFS_DIR3_FT_FIFO,
> -	[S_IFSOCK >> S_SHIFT]   = XFS_DIR3_FT_SOCK,
> -	[S_IFLNK >> S_SHIFT]    = XFS_DIR3_FT_SYMLINK,
> +const unsigned char xfs_dtype_to_ftype[S_DT_MAX+1] = {
> +	[0]                = XFS_DIR3_FT_UNKNOWN,
> +	[S_DT(S_IFREG)]    = XFS_DIR3_FT_REG_FILE,
> +	[S_DT(S_IFDIR)]    = XFS_DIR3_FT_DIR,
> +	[S_DT(S_IFCHR)]    = XFS_DIR3_FT_CHRDEV,
> +	[S_DT(S_IFBLK)]    = XFS_DIR3_FT_BLKDEV,
> +	[S_DT(S_IFIFO)]    = XFS_DIR3_FT_FIFO,
> +	[S_DT(S_IFSOCK)]   = XFS_DIR3_FT_SOCK,
> +	[S_DT(S_IFLNK)]    = XFS_DIR3_FT_SYMLINK,
>  };
>  
>  /*
> diff --git a/fs/xfs/libxfs/xfs_dir2.h b/fs/xfs/libxfs/xfs_dir2.h
> index 0197590..4934d38 100644
> --- a/fs/xfs/libxfs/xfs_dir2.h
> +++ b/fs/xfs/libxfs/xfs_dir2.h
> @@ -35,7 +35,9 @@ extern struct xfs_name	xfs_name_dotdot;
>   * directory filetype conversion tables.
>   */
>  #define S_SHIFT 12
> -extern const unsigned char xfs_mode_to_ftype[];
> +#define S_DT(mode)     (((mode) & S_IFMT) >> S_SHIFT)
> +#define S_DT_MAX       S_DT(S_IFMT)
> +extern const unsigned char xfs_dtype_to_ftype[];
>  
>  /*
>   * directory operations vector for encode/decode routines
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 308bebb..d2da9ca 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -103,7 +103,7 @@ xfs_dentry_to_name(
>  {
>  	namep->name = dentry->d_name.name;
>  	namep->len = dentry->d_name.len;
> -	namep->type = xfs_mode_to_ftype[(mode & S_IFMT) >> S_SHIFT];
> +	namep->type = xfs_dtype_to_ftype[S_DT(mode)];
>  }
>  
>  STATIC void
> -- 
> 2.7.4
> 
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