Dave Kleikamp <dave.kleikamp@xxxxxxxxxx> writes:
> Ben Hutchings backported this patch that has just been picked up in the
> mainline kernel for 3.11. It is relevant to and should apply to any
> stable kernel between 2.6.32.x and 3.10.x. (Possibly further back, but
> does anyone care?)
>
> Upstream commit: 44512449c0ab368889dd13ae0031fba74ee7e1d2
Thanks. I'm queuing it for the 3.5 kernel.
Cheers,
--
Luis
>
> NFSv4 reserves readdir cookie values 0-2 for special entries (. and
>..),
> but jfs allows a value of 2 for a non-special entry. This incompatibility
> can result in the nfs client reporting a readdir loop.
>
> This patch doesn't change the value stored internally, but adds one to
> the value exposed to the readdir method.
>
> Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
> [bwh: Backported to 3.2:
> - Adjust context
> - s/ctx->pos/filp->f_pos/]
> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
> ---
> fs/jfs/jfs_dtree.c | 31 +++++++++++++++++++++++--------
> 1 file changed, 23 insertions(+), 8 deletions(-)
>
> diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
> index 8743ba9..0ec767e 100644
> --- a/fs/jfs/jfs_dtree.c
> +++ b/fs/jfs/jfs_dtree.c
> @@ -3047,6 +3047,14 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
>
> dir_index = (u32) filp->f_pos;
>
> + /*
> + * NFSv4 reserves cookies 1 and 2 for . and .. so we add
> + * the value we return to the vfs is one greater than the
> + * one we use internally.
> + */
> + if (dir_index)
> + dir_index--;
> +
> if (dir_index > 1) {
> struct dir_table_slot dirtab_slot;
>
> @@ -3086,7 +3094,7 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
> if (p->header.flag & BT_INTERNAL) {
> jfs_err("jfs_readdir: bad index table");
> DT_PUTPAGE(mp);
> - filp->f_pos = -1;
> + filp->f_pos = DIREND;
> return 0;
> }
> } else {
> @@ -3094,15 +3102,15 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
> /*
> * self "."
> */
> - filp->f_pos = 0;
> + filp->f_pos = 1;
> if (filldir(dirent, ".", 1, 0, ip->i_ino,
> DT_DIR))
> return 0;
> }
> /*
> * parent ".."
> */
> - filp->f_pos = 1;
> + filp->f_pos = 2;
> if (filldir(dirent, "..", 2, 1, PARENT(ip), DT_DIR))
> return 0;
>
> @@ -3123,24 +3131,25 @@ 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 = filp->f_pos;
> - if (dtpos == 0) {
> + if (dtpos < 2) {
> /* build "." entry */
>
> + filp->f_pos = 1;
> if (filldir(dirent, ".", 1, filp->f_pos, ip->i_ino,
> DT_DIR))
> return 0;
> - dtoffset->index = 1;
> + dtoffset->index = 2;
> filp->f_pos = dtpos;
> }
>
> if (dtoffset->pn == 0) {
> - if (dtoffset->index == 1) {
> + if (dtoffset->index == 2) {
> /* build ".." entry */
>
> if (filldir(dirent, "..", 2, filp->f_pos,
> @@ -3233,6 +3242,12 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
> }
> jfs_dirent->position = unique_pos++;
> }
> + /*
> + * We add 1 to the index because we may
> + * use a value of 2 internally, and NFSv4
> + * doesn't like that.
> + */
> + jfs_dirent->position++;
> } else {
> jfs_dirent->position = dtpos;
> len = min(d_namleft, DTLHDRDATALEN_LEGACY);
> --
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