[syslinux] [PATCH] xfs: Add support for v3 directories

[Gene Cumm]

On Mon, Dec 14, 2015 at 7:54 PM, Paulo Alcantara <pcacjr at gmail.com> wrote:
> Besides supporting newer version of xfs file system, this patch also
> does some code refactoring and fix completely broken listing and
> searching on v2-3 node directories.
>
> Cc: Gene Cumm <gene.cumm at gmail.com>
> Cc: H. Peter Anvin <hpa at zytor.com>
> Cc: Raphael S. Carvalho <raphael.scarv at gmail.com>
> Cc: Ady <ady-sf at hotmail.com>
> Signed-off-by: Paulo Alcantara <pcacjr at zytor.com>
> ---
>  core/fs/xfs/xfs.c         |  19 +--
>  core/fs/xfs/xfs.h         | 155 +++++++++++++++++++-----
>  core/fs/xfs/xfs_dinode.c  |   2 +-
>  core/fs/xfs/xfs_dir2.c    | 296 +++++++++++++++++++++++++---------------------
>  core/fs/xfs/xfs_dir2.h    |   6 +-
>  core/fs/xfs/xfs_readdir.c | 151 ++++++++++++++---------
>  6 files changed, 399 insertions(+), 230 deletions(-)

> diff --git a/core/fs/xfs/xfs_dir2.c b/core/fs/xfs/xfs_dir2.c
> index de37ef7..f738a58 100644

> --- a/core/fs/xfs/xfs_dir2.c
> +++ b/core/fs/xfs/xfs_dir2.c

> @@ -593,110 +628,99 @@ struct inode *xfs_dir2_node_find_entry(const char *dname, struct inode *parent,
>                                        xfs_dinode_t *core)
>  {

> -    uint32_t hash = 0;
> +    uint32_t hash;

> +    uint16_t count;

> -    int mid = 0;
> +    int mid;


> +    if (be16_to_cpu(lhdr->info.magic) == XFS_DIR2_LEAFN_MAGIC) {
> +       count = be16_to_cpu(lhdr->count);
> +       ents = (xfs_dir2_leaf_entry_t *)((uint8_t *)lhdr +
> +                                        sizeof(struct xfs_dir2_leaf_hdr));
> +    } else if (be16_to_cpu(lhdr->info.magic) == XFS_DIR3_LEAFN_MAGIC) {
> +       count = be16_to_cpu(((xfs_dir3_leaf_hdr_t *)lhdr)->count);
> +       ents = (xfs_dir2_leaf_entry_t *)((uint8_t *)lhdr +
> +                                        sizeof(struct xfs_dir3_leaf_hdr));
> +    } else {
> +        xfs_error("Leaf's magic number does not match (0x%04x)!",
> +                 be16_to_cpu(lhdr->info.magic));
>          goto out;
>      }
>
> -    if (!leaf->hdr.count)
> -        goto out;
> +    if (!count)
> +       goto out;
>
> -    for (lep = leaf->ents, low = 0, high = be16_to_cpu(leaf->hdr.count) - 1;
> -         low <= high; ) {
> +    lep = ents;
> +    low = 0;
> +    high = count - 1;
> +    while (low <= high) {
>          mid = (low + high) >> 1;
> -
>          if ((hash = be32_to_cpu(lep[mid].hashval)) == hashwant)
>              break;
>          if (hash < hashwant)

Paulo, the initialization to zero of hash and mid silences the
compiler's warning about potentially unitialized variables since some
versions aren't intelligent enough to realize you've checked for the
case of (count == 0), initialized low to 0 and therefore high must be
equal to or greater than low.

Other than this, it should be good.

-- 
-Gene