On Wed, Aug 14, 2013 at 10:54:31PM -0500, Dave Kleikamp wrote:
> For the sake of those not watching
> https://bugzilla.kernel.org/show_bug.cgi?id=60737
> 
> It looks like the problem is that jfs was using a cookie value of 2 for
> a real directory entry, where NFSv4 expect 2 to represent "..". This
> patch has so far only been lightly tested.
> 
> NFSv4 reserves cookie values 0, 1 and 2 for a rewind, and the "." and ".."
> entries. jfs was using 0 and 1 for "." and "..", but 2 for a regular entry.
> This patch makes jfs conform by using 1 and 2 for "." and ".." and fixes
> any regular entry using the value 2.

Oh, I'd forgotten that.  From rfc 5661:

        For some file system environments, the directory entries "." and
        ".." have special meaning, and in other environments, they do
        not.  If the server supports these special entries within a
        directory, they SHOULD NOT be returned to the client as part of
        the READDIR response.  To enable some client environments, the
        cookie values of zero, 1, and 2 are to be considered reserved.
        Note that the UNIX client will use these values when combining
        the server's response and local representations to enable a
        fully formed UNIX directory presentation to the application.

OK!

--b.

> 
> Signed-off-by: Dave Kleikamp <dave.kleik...@oracle.com>
> 
> diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
> index 8743ba9..93466e8 100644
> --- a/fs/jfs/jfs_dtree.c
> +++ b/fs/jfs/jfs_dtree.c
> @@ -349,11 +349,8 @@ static u32 add_index(tid_t tid, struct inode *ip, s64 
> bn, int slot)
>  
>       ASSERT(DO_INDEX(ip));
>  
> -     if (jfs_ip->next_index < 2) {
> -             jfs_warn("add_index: next_index = %d.  Resetting!",
> -                        jfs_ip->next_index);
> -             jfs_ip->next_index = 2;
> -     }
> +     if (jfs_ip->next_index < 3) {
> +             jfs_ip->next_index = 3;
>  
>       index = jfs_ip->next_index++;
>  
> @@ -2864,7 +2861,7 @@ void dtInitRoot(tid_t tid, struct inode *ip, u32 
> idotdot)
>               } else
>                       ip->i_size = 1;
>  
> -             jfs_ip->next_index = 2;
> +             jfs_ip->next_index = 3;
>       } else
>               ip->i_size = IDATASIZE;
>  
> @@ -2951,7 +2948,7 @@ static void add_missing_indices(struct inode *inode, 
> s64 bn)
>       for (i = 0; i < p->header.nextindex; i++) {
>               d = (struct ldtentry *) &p->slot[stbl[i]];
>               index = le32_to_cpu(d->index);
> -             if ((index < 2) || (index >= JFS_IP(inode)->next_index)) {
> +             if ((index < 3) || (index >= JFS_IP(inode)->next_index)) {
>                       d->index = cpu_to_le32(add_index(tid, inode, bn, i));
>                       if (dtlck->index >= dtlck->maxcnt)
>                               dtlck = (struct dt_lock *) txLinelock(dtlck);
> @@ -3031,7 +3028,7 @@ int jfs_readdir(struct file *file, struct dir_context 
> *ctx)
>       struct jfs_dirent *jfs_dirent;
>       int jfs_dirents;
>       int overflow, fix_page, page_fixed = 0;
> -     static int unique_pos = 2;      /* If we can't fix broken index */
> +     static int unique_pos = 3;      /* If we can't fix broken index */
>  
>       if (ctx->pos == DIREND)
>               return 0;
> @@ -3039,15 +3036,16 @@ int jfs_readdir(struct file *file, struct dir_context 
> *ctx)
>       if (DO_INDEX(ip)) {
>               /*
>                * persistent index is stored in directory entries.
> -              * Special cases:        0 = .
> -              *                       1 = ..
> +              * Special cases:        0 = rewind
> +              *                       1 = .
> +              *                       2 = ..
>                *                      -1 = End of directory
>                */
>               do_index = 1;
>  
>               dir_index = (u32) ctx->pos;
>  
> -             if (dir_index > 1) {
> +             if (dir_index > 2) {
>                       struct dir_table_slot dirtab_slot;
>  
>                       if (dtEmpty(ip) ||
> @@ -3090,18 +3088,18 @@ int jfs_readdir(struct file *file, struct dir_context 
> *ctx)
>                               return 0;
>                       }
>               } else {
> -                     if (dir_index == 0) {
> +                     if (dir_index < 2) {
>                               /*
>                                * self "."
>                                */
> -                             ctx->pos = 0;
> +                             ctx->pos = 1;
>                               if (!dir_emit(ctx, ".", 1, ip->i_ino, DT_DIR))
>                                       return 0;
>                       }
>                       /*
>                        * parent ".."
>                        */
> -                     ctx->pos = 1;
> +                     ctx->pos = 2;
>                       if (!dir_emit(ctx, "..", 2, PARENT(ip), DT_DIR))
>                               return 0;
>  
> @@ -3122,22 +3120,24 @@ int jfs_readdir(struct file *file, struct dir_context 
> *ctx)
>               /*
>                * Legacy filesystem - OS/2 & Linux JFS < 0.3.6
>                *
> -              * pn = index = 0:      First entry "."
> -              * pn = 0; index = 1:   Second entry ".."
> +              * pn = 0; index = 1:   First entry "."
> +              * pn = 0; index = 2:   Second entry ".."
>                * pn > 0:              Real entries, pn=1 -> leftmost page
>                * pn = index = -1:     No more entries
>                */
>               dtpos = ctx->pos;
> -             if (dtpos == 0) {
> +             if (dtpos < 2) {
> +                     ctx->pos = 1;
>                       /* build "." entry */
>                       if (!dir_emit(ctx, ".", 1, ip->i_ino, DT_DIR))
>                               return 0;
> -                     dtoffset->index = 1;
> +                     dtoffset->index = 2;
>                       ctx->pos = dtpos;
>               }
>  
>               if (dtoffset->pn == 0) {
> -                     if (dtoffset->index == 1) {
> +                     if (dtoffset->index == 2) {
> +                             ctx->pos = 2;
>                               /* build ".." entry */
>                               if (!dir_emit(ctx, "..", 2, PARENT(ip), DT_DIR))
>                                       return 0;
> @@ -3210,8 +3210,12 @@ int jfs_readdir(struct file *file, struct dir_context 
> *ctx)
>                                * directory index for the lost+found
>                                * directory.  Rather than let it go,
>                                * we can try to fix it.
> +                              *
> +                              * Additionally, a value of 2 used to be
> +                              * valid, but it didn't work well with
> +                              * NFSv4, so if found, we need to change it
>                                */
> -                             if ((jfs_dirent->position < 2) ||
> +                             if ((jfs_dirent->position < 3) ||
>                                   (jfs_dirent->position >=
>                                    JFS_IP(ip)->next_index)) {
>                                       if (!page_fixed && !isReadOnly(ip)) {


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